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2025届高三9月质量检测化学全卷满分100分,考试时间75分钟。
注意事项:1.答题前,先将自己的姓名、准考证号填写在试卷和答题卡上,并将条形码粘贴在答题卡上的指定位置。
2.请按题号顺序在答题卡上各题目的答题区域内作答,写在试卷、草稿纸和答题卡上的非答题区域均无效。
3.选择题用2B 铅笔在答题卡上把所选答案的标号涂黑;非选择题用黑色签字笔在答题卡上作答;字体工整,笔迹清楚。
4.考试结束后,请将试卷和答题卡一并上交。
可能用到的相对原子质量:H1 B11 C12 N14 O16 S32 Cl35.5 Ca40 Fe56一、选择题:本题共14小题,每小题3分,共42分。
在每小题给出的四个选项中,只有一项符合题目要求。
1.化学与科技创新密切相关。
下列说法错误的是( )A.“快舟一号甲”运载火箭利用燃料与氧化剂反应放热并产生大量气体实现助推B.“天目一号”气象星座卫星的光伏发电系统工作时可将化学能转化为电能C “爱达·魔都号”邮轮使用的镁铝合金具有密度低、抗腐蚀性强的特点D.“AG60E ”电动飞机使用的动力型锂电池具有质量轻、比能量高的特点2.下列化学用语表述正确的是( )A.基态Cr 原子的价层电子排布图为B.的化学名称为甲基丁烯C.分子的VSEPR 模型为D.用电子式表示的形成过程为:3.下列生产活动中对应的离子方程式正确的是( )A.铅酸蓄电池充电时的阳极反应:B.向冷的石灰乳中通入制漂白粉:C.用溶液除去锅炉水垢中的:D.用葡萄糖制镜或保温瓶胆:()332CH CH C CH =3-2--3NH 2CaCl 222Pb 2H O 2e PbO 4H +-++-=+2Cl 22Cl 2OH Cl ClO H O---+=++23Na CO 4CaSO 224334CaSO (s)CO (aq)CaCO (s)SO (aq)--++A()2432CH OH(CHOH)CHO 2Ag NH OH ⎡⎤+−−→⎣⎦△24432CH OH(CHOH)COO NH 2Ag 3NH H O-+++↓++4.某化学兴趣小组进行如下实验:实验①:向晶体中滴加浓盐酸,产生黄绿色气体。
讨论中国说唱传统对韩国盘索里发展产生影响的可能性纵观历史,朝鲜半岛不仅从中国引入了世俗音乐和宗教音乐,也引进了礼仪文化和戏剧文化。
例如,赞美佛陀的梵呗( pǒmp’ae) 便是在统一的新罗时期( 668 - 918) 传入朝鲜半岛。
高丽时期( 918 - 1392) 则见证了一种被称为傩礼( Narye)的宫廷仪式( 字面上的意思为驱除邪恶的仪式)的传人。
这种习俗一直持续到中国京剧( 朝鲜语称之为kyǒnggǔk) 传入朝鲜半岛的十九世纪末,盘索里的一个现代形式唱剧( ch’anggǔk) 可能就是受其影响而产生。
在历史上的很长一段时间里,韩国作为附属国常年向中国进贡。
这种朝贡关系从三国时期( 公元前18 - 公元668) 持续到朝鲜王朝后期。
相比中国,韩国是一个小国,效仿着中国的文化和艺术。
那时,中国被韩国人称作大国( taeguk) 。
《三国史记》中记载,“新罗王国时期,韩国官员和普通百姓穿着中国服饰”( 译自韩国Chosǒn inminchuǔi inmin konghwaguk kwahagwǒn kojǒn yǒn’gusil,1959: 136) 。
高丽时期,唐乐( Tangak) 和宋代俗乐传入。
从后来的资料中我们得知,唐乐被用于宫廷的各种祭祀仪式中,比如孔庙( Kongjamyo) 和太庙( T’aemyo,为王朝创始者朝鲜太祖举行的仪式) 。
引进中国乐器也是顺应中国文化的一部分。
1114 年,高丽王朝睿宗皇帝( 1106 - 1122) 统治时期便从中国宋朝引进了许多乐器( 详见SongBang - song,1980: 144 - 6; Lee Hye - gu [YiHyegu],1977: 42,以及Keith Pratt,1987: 65) 。
一直到朝鲜王朝时期,朝鲜半岛都从中国进口乐器。
在孝宗李淏统治时期( 1649 - 1659 ) ,Changagwǒn ( 皇宫音乐机构) 的许喜( HǒHǔi)上报皇帝说,一些国家祭祀音乐中用到的乐器在16 世纪90 年代日军进犯时被摧毁。
些溶剂的介电常数介电常数(Dielectric constants)表1列出常见气体在20°C, 101 325 Pa条件下的介电常识(£ )。
数据中的有效数字表示测试精度,其中Ar, H2, He , N 2, O2, CO2等被推荐为参比数据,其精度为百万分之一或更高。
1气体的介电常数(D feJectric constants ofgases )表1 气体的介电常数Tabb 1 D ielectrr constants ofgases化学式C hem ralfom ula 名称D enom nationEAr(不含碳物质)空气(干基,无C0 2)氮1.00053641.0005172BF3 三氟化硼 1.0011 HBr 澳化氢 1.00279 HC1 氯化氢 1.00390 HI 碘化氢 1.00214 H 2 氢 1.0002538 H2S 硫化氢 1.00344 He M 1.0000650 Kr 氮 1.00078 NFs 三氟化氮 1.0013 NH 3 氨 1.00622 NO 一氧化氮 1.00060 N 2 氮 1.0005480 N 2O 一氧化二氮 1.00104 Ne M 1.00013 O2 氧 1.0004947 Os 臭氧 1.0017 SFe 六氟化硫 1.00200 SO2 二氧化硫 1.00825 XE 1.00126CF4 (含碳物质)四氟甲烷 1.00121CO 一氧化碳 1.00262 CO2 二氧化碳 1.000922CH sBr 澳代甲烷 1.01028 CH sCl 氯代甲烷 1.01080CH F氟代甲烷 1.00973 3CHs I 碘代甲烷 1.00914CH4 甲烷 1.00081C2H 2 乙烘 1.00124C2H3CI 氯乙烯 1.0075C2H 4 乙烯 1.00134C2H5C1 氯乙烷 1.01325C2H 6 乙烷 1.00140C2H 60 甲醛 1.0062CsH 6 丙烯 1.00228CsH 6 环丙烷 1.00178CsH 6 丙烷 1.00200C 4 H 10 丁烷 1.00258C 4 H 10 异丁烷 1.00260 2饱和水蒸气的介电常数(D ielectric constants of saturated watervapor ) 表2给出不同温度下的液态水成平衡的水蒸气的介电常数。
专题02 认识23个声母(学生版)幼小衔接指的是幼儿教育与小学教育的衔接。
处于幼儿园与小学阶段的学童具有不尽相同的身心发展特征,解决好幼儿教育与小学教育的衔接问题,对于促进人的可持续发展,提高教育质量都具有重要意义。
一、衔接要点二、知识平台1.认识23个声母。
像个6字 b b b,脸盆泼水 p p p,两个门洞 m m m,一根拐棍 f f f两个门洞 m m m,一根拐棍 f f f左下半圆 d d d,雨伞把子t t t,一个门洞 n n n,一根小棍 l l l9字加钩g g g,机枪向上k k k,一把椅子h h hi下加钩j j j,像个9字q q q,一个“X”字x x x像个2字z z z ,半个圆圈 c c c,半个8字s s sz加椅子zh zh zh, c加椅子 ch ch ch,s加椅子sh sh sh,禾苗向日r r r。
*其中zh ch sh r是翘舌音,也叫卷舌音;z c s是平舌音。
y 字好像小树杈,挂件衣服yyy w 字好像小屋顶,乌龟小屋www 2.书写(1)复习四线三格(2)声母所在四线三格的位置。
(3)书写笔画。
三、声母分类翘舌音: zh、ch、sh、r平舌音:z、c、s鼻音:n边音:l一、选择题。
1.下列汉字声母是b韵母是ei的是()A.岁B.北C.色D.车2.选出声母不同类的一项()A.爸B.布C.衣D.笔3.声母为“ ch r”的是()A.我日B.齿日C.十从D.车思4.下列汉字声母为“z c s”的是()A.我哥福B.卢从四C.责几色D.自次三5.下列汉字声母是c的是()A.火克B.词蚕C.菜上D.吃木6.选出声母不同类的一项。
()A.目B.丘C.千D.且7.选出声母不同类的一项()A.大B.地C.笔D.弟8.下列汉字声母是n的()A.李B.你C.了D.力9.下列汉字声母是g和k的是()A.马克B.干开C.了合D.力雨10.下面汉字声母都是z和韵母都是ai的一组是()A.宅、火B.你、水C.在、仔D.斋、在11.下列汉字声母是ch的是()A.火你B.车产C.木上D.吃她12.选出声母不同类的一项()A.木B.客C.口D.看13.选出声母不一样的一项()A.火自B.词丛C.福父D.五我14.选出声母不同类的一项。
文章标题:深度解析aeo-14 壬基酚聚醚-14质量标准一、引言在化工行业中,壬基酚聚醚-14 (AEO-14)作为一种非离子表面活性剂,具有优异的乳化、分散、增溶、润湿等性能,广泛应用于纺织、印染、制革、油田、农药、清洁剂等领域。
而AEO-14的质量标准,对于保证产品质量、提高生产效率至关重要。
本文将对AEO-14的质量标准进行深度解析,帮助读者更全面地了解这一重要的标准。
二、AEO-14的基本性质AEO-14是一种疏水性比较强的非离子表面活性剂,其主要特性包括界面活性、乳化性能、分散性能、表面张力等。
AEO-14的质量标准需要从这些方面进行评估。
1. 界面活性AEO-14的界面活性是其重要性能之一,直接影响到其乳化、分散等功能。
在制定质量标准时,需要对界面活性的指标进行严格要求,确保产品在不同环境下都能保持稳定的界面活性。
2. 乳化性能AEO-14作为乳化剂,其乳化性能是衡量其质量的重要指标之一。
质量标准需要明确规定AEO-14在不同温度、PH值下的乳化性能,以及对不同类型油脂的乳化能力。
3. 分散性能AEO-14还具有良好的分散性能,对颗粒物料的分散效果直接关系到产品的使用效果。
质量标准中需要对AEO-14的分散性能做出详细的要求和检测方法。
4. 表面张力AEO-14的表面张力直接关系到其润湿性能,而润湿性能又与产品的加工工艺、使用效果密切相关。
质量标准中对AEO-14的表面张力也需要有一定的规定。
三、AEO-14的质量标准了解了AEO-14的基本性质,接下来我们将结合这些性能对AEO-14的质量标准进行深度解析。
1. 外观要求AEO-14作为一种化工产品,其外观质量直接关系到产品的使用安全性和美观性。
质量标准中应该包括对AEO-14外观的要求,例如颜色、透明度等指标。
2. 含量检测AEO-14的含量直接关系到其使用效果,因此质量标准中需要对AEO-14的含量进行严格检测,并确保其符合规定的范围。
aeo-14 壬基酚聚醚-14 质量标准一、引言壬基酚聚醚-14是一种常用的表面活性剂,被广泛应用于各个领域,包括家居清洁产品、个人护理品、工业清洁剂等。
为了确保产品的质量和安全性,制定壬基酚聚醚-14的质量标准至关重要。
本文将从外观性状、主要成分、理化性质、纯度、溶解性、微生物限度等方面,详细介绍壬基酚聚醚-14质量标准的要求。
二、外观性状要求壬基酚聚醚-14的外观应为无色或微黄色透明液体。
在质量标准中,应明确外观色泽的范围,并规定了允许的色度、透明度要求,以确保产品在质量上符合要求。
三、主要成分检测壬基酚聚醚-14的主要成分是壬基酚聚氧乙烯醚,因此质量标准中应规定主要成分含量的要求。
一般以氧乙烯基团数来表示其含量,要求明确规定壬基酚聚氧乙烯醚含量的下限和上限,以保证产品的一致性和稳定性。
四、理化性质要求1. 密度:壬基酚聚醚-14的密度是其物理性质之一,通过密度的要求,可以确保产品的质量和规范性。
2. 相对分子质量:通过相对分子质量的要求,可以验证壬基酚聚醚-14的纯度和化学组成,确保产品的质量标准。
五、纯度检测壬基酚聚醚-14的纯度是保证产品质量的重要指标,质量标准中应规定壬基酚聚醚-14的纯度要求,一般用含量值来表示。
此外,还可以根据不同行业的需求,对有害杂质的含量进行限制。
六、溶解性要求壬基酚聚醚-14的溶解性影响着其在不同产品中的应用效果。
质量标准中应规定壬基酚聚醚-14的溶解性要求,可以根据产品的使用环境来制定相关标准,以确保产品能够正常溶解并发挥其应有的功能。
七、微生物限度壬基酚聚醚-14作为一种表面活性剂,其微生物限度是确保产品安全性和稳定性的重要要求之一。
质量标准中应包括壬基酚聚醚-14的微生物限度要求,包括菌落总数、大肠菌群和真菌、酵母菌等指标的检测和要求。
八、结论本文对壬基酚聚醚-14的质量标准进行了全面的论述,从外观性状、主要成分、理化性质、纯度、溶解性和微生物限度等方面进行了详细介绍。
c6h14的所有构造异构体的构造式文章标题:深度探究C6H14的所有构造异构体的构造式目录1. 引言2. C6H14的构造异构体概述3. 探索正构烷的构造式4. 研究异构体的构造式5. 总结与回顾6. 个人观点与理解引言C6H14是己烷的分子式,它是一个有趣和重要的化学化合物。
在本文中,我们将深入探讨C6H14的所有构造异构体的构造式,从简到繁地探讨这一主题,让我们一起开始这次精彩的化学之旅。
C6H14的构造异构体概述C6H14是己烷的简单化合物,但是它却有多种构造异构体。
构造异构体是指分子式相同但结构不同的化合物。
对于C6H14来说,它有多种构造异构体,包括正构烷和异构烷。
接下来,我们将分别探讨这些构造异构体的构造式。
探索正构烷的构造式正构烷是一类结构简单的构造异构体,它的分子式为CnH2n+2。
对于C6H14来说,它的正构烷包括正己烷和异戊烷。
在化学结构上,正己烷的分子式为CH3(CH2)4CH3,而异戊烷的分子式为CH3CH2CH(CH3)CH2CH3。
通过这些构造式,我们能够清晰地了解它们的化学结构和分子构型。
研究异构体的构造式除了正构烷,C6H14还有许多其他异构体,它们的构造式更加复杂和多样化。
其中包括立体异构体和链式异构体。
立体异构体的构造式常常涉及立体化学和手性分子,它们的空间结构对于化学性质和反应有着重要影响。
而链式异构体的构造式则涉及碳骨架的连接方式和分支位置,这也对化合物的性质产生深远影响。
通过对这些异构体构造式的研究,我们可以更加全面地了解C6H14的多样化结构和化学性质。
总结与回顾在本文中,我们深入探讨了C6H14的构造异构体的构造式。
从简到繁地探讨了正构烷和异构烷的构造式,以及立体异构体和链式异构体的构造式。
通过这次探究,我们对C6H14的多样化结构有了更深入的理解,也对化学中构造异构体的研究有了更加全面的认识。
个人观点与理解对于C6H14的构造异构体的研究,我深切体会到化学世界的复杂和多样化。
通识教育平台下的性健康教育课程对大学生性知识的干预效果评价邸丽华,向兵,曾婧,杨梅,彭雨霜,周伽,翟小兵【摘要】目的评估通识教育平台下性健康教育课程对大学生性知识认知的干预效果。
方法抽取某高校部分大学生为研究对象分为3组:自愿选修《性与健康》的学生作为课程干预组,课程干预组进行5周(2次/周)的课堂教学。
接受课程干预组转述课程内容的学生为同伴教育组,未与课程干预组交流的学生为对照组。
在T9、T、T3个时间点对3组进行性知识问卷调查,采用重复测量方差分析、独立样本t检验等统计学分析方法。
结果重复测量方差分析结果显示:3组性生理知识(F=5.489,P<0.001;F=9.998,P<0.001)、避孕及安全套使用知识(F=5.545,P<0i001;F=7i910,P=0.001)和性传播疾病及艾滋病知识(F=24.711,P< 5001;F-10.093,P<0.001)组间和时间主效应差异有统计学意义;且性生理知识(F=2.600,P=0.036)、避孕及安全套使用知识(F=3.877,P=0.004)组间*时间有交互作用。
课程干预组比同伴教育组在T得分明显增加。
对不同时点3组各维度得分差异比较显示,在T1、T4课程干预组与同伴组教育组和对照组得分相比有明显提高,差异有统计学意义(P<0.05)。
不同时间点的两两比较显示,课程干预组各维度知识得分在T9、T、T4两两比较差异均有统计学意义(P<0.45)。
结论通识教育平台下性教育课程明显提升了大学生性知识水平,直接参与课程比同伴教育成效更好。
【关键词】性健康教育;大学生;性知识;通识教育;同伴教育;重复测量方差分析【中图分类号】R53【文献标识码】A【文章编号】1002-9982(205-)03-0534-05DOI:14.19193/ji cnki.issu.1002-9982.202-.43.009Inteevention effect of sexual health enuchUon churses on sexual knowledge by generol educction platform among Chlleae sthdents DE Li-Xua,XIANG Bing,ZENG Jing,YANG Mai,PENG Y-Xioang,ZHOE Jio,ZHAI Xiao-bingi School o-Public Healti,Menical Collegn,Wuhan Enwersiti af Scienca ant Tecanologa,Maternal ant Child Research Centne,MedOat Collegr,Wuhan EnWeaUy o-Science ann Technodga,WuUan434065,Chiua【Abshoch Objective To evaluate the intervex/on eXect oS sexual health ehuca/on courses by the general0X00-Uon pPUorm on college8/06/('copnition oS sexual kkowPhye.Methods College students from a university were selected as the research okjects and diviPeh into3groups:students who voP/ariD took"Sex and Health"as the carricalum DP s-ven/on group and had5weeds(2times/xeeh)oS classroom teachingi The students who received the carricalum content oS the carricalum intervention group were as peer ePoca/on group,and the students who did uot communicate with-ho caracm Pm interven/on group were as control group.At three Umo points oS T1,T],and T2,the three groups were surveyed on sexual kuowPPgc qoes/onnaDes ,and data were analyzed by using ANCOVAs,Ddependent sample t-test and other s P/s-Ucai analysis methoks.Reshlts The results oS ANCOVAs showed:main efects oS intervention and/me on sexual physiology kuowlehgc(F=5i489,P<0.001;F二9.998,P<0.001),contracepUve and condom kuowlehye(F二5.545,P< 5001;F=7.910,P二0.001)—d kuowlehgc oS sexually trausmined diseases and AIDS(F=22.711,P<0.001;F-10i093,P<0.001)among3groups were significa/p.And sexual physiology kuowlehgc(F二2.640,P二0.036),0/ WacepUve and condom kuowlehgc(F=3.877,P二0.404)had interaction effect between groups and time.The carricalum interven/on group changeP more okviousp than pees ehoca/on group in T].The diDerence oS kuowlehgc scores between the three groups at diDerent time points showed that the score oS carricalum Dterven/ou group was significan/y h/her than that oS peer group education group and control group at T,T2,and there was significant diDerence(P<0.45).The comparison oS diDereut/me points showed that there were significant differeuces in the kuowledge scores oS each dimension oS the course interven/on group at To,T,T2(P<0.45).Conclusion The level oS sexual kuowlePgc oS college students were okviousp improved by the seu edoca/on courses uodvr the general edoca/on pPWorm.The eXect oS direct paaicipa/on in courses were better than that oS peer eUoca/on.【Key words】Sexuvl health edoca/on;College students;Sexuvl kuowlePgc;General ehoca/on;Peer ePocaUon;AN-COVAs【基金项目】2919年武汉科技大学教研项目:高校通识教育学生成绩多元评价指标体系的构建与应用研究(2919X975)【作者单位】武汉科技大学医学院公共卫生与预防医学院,湖北武汉430065【作者简介】邸丽华(1994-),女,甘肃张掖人,硕士在读,主要从事儿少卫生与妇幼保健研究。
㊃综述㊃d o i:10.3969/j.i s s n.1671-8348.2023.07.022网络首发h t t p s://k n s.c n k i.n e t/k c m s/d e t a i l//50.1097.R.20230210.1409.004.h t m l(2023-02-13)仿生矿化胶原材料应用于引导骨再生术的研究进展*马士卿1,王晓婧2综述,彭诚1ә审校(1.天津医科大学第二医院口腔科300211;2.天津医科大学口腔医学院300070)[摘要]以仿生学为指导研发的仿生矿化胶原材料具有优异的生物可吸收性㊁骨传导性和明显高于传统胶原材料的机械强度㊂在生物活性因子的修饰下,它们还能够激活相关信号通路㊁调节成骨相关基因表达㊁诱导干细胞的成骨分化㊂仿生矿化胶原材料通常以屏障膜的形式在引导性骨再生(G B R)术中广泛应用,并凭借其良好的生物可吸收性和较少的术后并发症而逐渐取代传统的不可吸收膜㊂本文回顾了胶原蛋白矿化的基本原理,并详细论述了仿生矿化胶原材料在临床G B R术中的应用策略㊂[关键词]胶原;仿生矿化;引导性骨再生;颌面骨缺损[中图法分类号] R782.13[文献标识码] A[文章编号]1671-8348(2023)07-1072-06 R e s e a r c h p r o g r e s s o n b i o m i m e t i c m i n e r a l i z e d c o l l a g e n m a t e r i a l su s e d i n g u i d e d b o n e r e g e n e r a t i o nMA S h i q i n g1,WA N G X i a o j i n g2,P E N G C h e n g1ә(1.D e p a r t m e n t o f S t o m o t o l o g y,t h e S e c o n d H o s p i t a l o f T i a n j i n M e d i c a l U n i v e r s i t y,T i a n j i n300211,C h i n a;2.C o l l e g e o f S t o m a t o l o g y,T i a n j i n M e d i c a l U n i v e r s i t y,T i a n j i n300070,C h i n a)[A b s t r a c t] B i o m i m e t i c m i n e r a l i z e d c o l l a g e n m a t e r i a l s d e v e l o p e d u n d e r t h e g u i d a n c e o f b i o n i c s r e p r e s e n t e x c e l l e n t b i o l o g i c a l a b s o r b a b i l i t y,o s t e o c o n d u c t i o n a n d m e c h a n i c a l s t r e n g t h s i g n i f i c a n t l y h i g h e r t h a n t r a d i t i o n a l c o l l a g e n m a t e r i a l s.W i t h t h e m o d i f i c a t i o n o f b i o a c t i v e f a c t o r s,t h e y c a n a l s o a c t i v a t e r e l e v a n t s i g n a l p a t h w a y s, r e g u l a t e t h e e x p r e s s i o n o f o s t e o g e n i c g e n e s,a n d i n d u c e t h e o s t e o g e n i c d i f f e r e n t i a t i o n o f s t e m c e l l s.B i o m i m e t i c m i n e r a l i z e d c o l l a g e n m a t e r i a l s a r e w i d e l y u s e d i n g u i d e d b o n e r e g e n e r a t i o n(G B R)i n t h e f o r m o f b a r r i e r m e m-b r a n e,a n d g r a d u a l l y r e p l a c e t h e t r a d i t i o n a l n o n-a b s o r b a b l e m e m b r a n e d u e t o t h e i r g o o d b i o a b s o r b a b i l i t y a n d f e w e r p o s t o p e r a t i v e c o m p l i c a t i o n s.T h i s p a p e r r e v i e w e d t h e b a s i c p r i n c i p l e o f c o l l a g e n m i n e r a l i z a t i o n,a n d d i s-c u s s e d t h e a p p l i c a t i o n s t r a t e g i e s o f b i o m i m e t i c m i n e r a l i z e d c o l l a g e n m a t e r i a l s i n c l i n i c a l G B R i n d e t a i l.[K e y w o r d s]c o l l a g e n;b i o m i m e t i c m i n e r a l i z a t i o n;g u i d e d b o n e r e g e n e r a t i o n;m a x i l l o f a c i a l b o n e d e f e c t骨组织有一定的再生能力,在缺损范围较小时可实现自我修复,然而这种能力十分有限,对于较大范围的骨缺损仍需手术干预[1]㊂目前,已有大量研究证实了引导性骨再生(g u i d e d b o n e r e g e n e r a t i o n,G B R)术作为骨增量手术的科学性和有效性[2]㊂仿生矿化研究为骨组织工程材料的制备提供新思路,对骨缺损的修复有十分重要的意义㊂本文重点论述了胶原蛋白矿化的基本原理及仿生矿化胶原材料在G B R中的应用进展㊂1 G B R的研究进展近年来,G B R术已成为治疗骨缺损的主要手段㊂该技术利用膜性材料作为屏障严密覆盖骨缺损区表面,防止缺损区外部生长较快的上皮和结缔组织细胞长入,形成一个相对封闭的空间以期缺损区内生长较慢的成骨细胞优先成骨[3]㊂G B R膜是该技术中不可或缺的一部分,它不仅发挥着屏障作用和骨传导作用,还可稳定血凝块和骨移植物,避免新骨形成前骨缺损区的塌陷[4]㊂根据膜材料是否具有生物可降解性,可将其分为不可吸收性膜和可吸收性膜㊂以聚四氟乙烯(p o l y t e t r a f l u r o e t h y e l e n e,P T F E)膜和钛网为代表的不可吸收性膜具有优异的机械性能,但其生物不可降解性伴随着黏膜开裂㊁膜暴露㊁感染等并发症2701重庆医学2023年4月第52卷第7期*基金项目:国家自然科学基金项目(81701019)㊂作者简介:马士卿(1991-),主治医师,博士,主要从事口腔医学种植体表面改性㊁引导组织再生研究㊂ә通信作者,E-m a i l:p e n g-c h e n g2013@163.c o m㊂Copyright©博看网. All Rights Reserved.及二次手术取出的额外痛苦,在临床上已很少应用[5-6]㊂而胶原膜㊁聚乳酸(p o l y l a c t i c a c i d,P L A)膜和聚乙醇酸(p o l y g l y c o l i c a c i d,P G A)膜等可吸收性膜不仅具有优异的生物相容性和生物活性,其特有的生物可降解性可使患者免受二次手术的痛苦,且术后伤口开裂和膜暴露的风险明显低于不可吸收性膜[7-9]㊂然而,可吸收性膜机械性能差㊁空间维持能力不足和降解速率难控制等缺点会对临床治疗效果造成一定影响[10]㊂被填充于骨缺损区的骨移植材料是G B R术中另一关键材料,它为成骨细胞的黏附㊁增殖和迁移提供支架,促进早期细胞成骨分化和基质生物矿化[11]㊂大量研究表明,以仿生学为指导原则开发的仿生矿化胶原材料具有优异的生物可吸收性㊁骨传导性和明显高于传统胶原材料的机械强度,甚至能够激活相关信号通路㊁调节成骨相关基因表达㊁诱导干细胞的成骨分化,这与其高度类似天然骨组织的化学组成及微观结构密不可分[12]㊂2胶原蛋白矿化的基本原理生物矿化是骨组织形成的基础,其核心内容是钙㊁磷等无机离子在非胶原蛋白(n o n c o l l a g e n o u s p r o-t e i n s,N C P s)等有机物的调控下成核㊁生长,并与胶原蛋白形成的胶原纤维结合而形成机体的矿化组织[13]㊂研究发现,矿化组织内的无机矿物质主要是纳米羟基磷灰石(h y d r o x y a p a t i t e,H A)晶体,而分布于胶原纤维不同部位的晶体的形态结构有明显差别 胶原纤维内的H A为板状纳米晶体,其c轴大致平行于胶原纤维的长轴;胶原纤维外的HA则是无明确晶体取向的晶体聚集体[14]㊂与外矿化的胶原纤维比较,发生内矿化的胶原纤维在机械性能和骨诱导能力等方面显示出明显的优势㊂这种差异源于自组装胶原纤维对其内部矿物质生长的空间限制效应及多种生物因子的调控,有大量研究试图详细描述胶原纤维内矿化的具体机制,至今已有各种不同的假说被提出[15]㊂如表1所示,最具代表性的6种假说分别是聚合物诱导液相前驱体(p o l y m e r i n d u c e d l i q u i d p r e c u r s o r s, P I L P)假说㊁自组装/矿化协同假说㊁库仑引力诱导胶原纤维矿化假说㊁渗透压/电荷双平衡诱导矿化假说㊁抑制剂排除矿化假说和界面能引导矿化假说,但都存在争议或论证不足之处[16-19]㊂迄今为止,虽然仍无理论能够从胶原蛋白基质㊁矿物前体和生物大分子诱导物及其相互作用等各方面完美诠释胶原蛋白矿化机制,但为胶原蛋白的体外矿化提供了灵感,对仿生矿化胶原材料的制备有重要的指导意义㊂表1胶原蛋白矿化假说的总结与比较矿化假说主要内容是否添加诱导物矿化特点争议点P I L P假说用N C P s类似物稳定无定型矿物前体,使之以矿化液滴的形式进入胶原纤维内部是胶原纤维内矿化液态前驱体是否通过毛细管作用进入胶原纤维内部有待实验证明自组装/矿化协同假说在高浓度的酸性胶原蛋白基质中引入高浓度的矿物前体,使胶原蛋白自组装和矿化协同进行否胶原纤维外矿化操作复杂且难以实现胶原纤维内矿化,该方法很少被采用库仑引力诱导胶原纤维矿化假说成核位点富含净正电荷,与用于稳定无定型前体的聚阴离子电解质产生库仑引力是胶原纤维内矿化聚阳离子电介质的作用机制无法用库仑引力来解释渗透压/电荷双平衡诱导矿化假说由电荷分布驱动的库仑引力和由渗透压驱动的渗透力都是诱导矿化前驱体进入胶原纤维内部的动力是胶原纤维内矿化仍需开展更多实验来对该猜想进行佐证抑制剂排除矿化假说因相对分子质量过大(>40ˑ103)而无法进入胶原纤维内部的N C P s可通过抑制胶原纤维外矿化来间接促进胶原纤维内矿化是胶原纤维内矿化N C P s的抑制剂效应主要与其本身的性质相关,而非其分子大小界面能引导矿化假说成核抑制剂通过增加磷酸钙核与矿化液体之间的界面能来抑制胶原纤维外矿化,从而促进磷酸钙核进入胶原纤维内部是胶原纤维内矿化该假说忽略了小分子成核抑制剂扩散到胶原纤维内部的情况3仿生矿化胶原材料在G B R中的应用3.1仿生矿化胶原材料应用于G B R的相关机制天然骨组织是以矿化胶原纤维为最基本结构单位的高度有序的有机-无机复合结构,其有机相的主要成分是Ⅰ型胶原蛋白分子自组装而成的Ⅰ型胶原纤维,作为主要无机相的纳米H A晶体[分子式为C a103701重庆医学2023年4月第52卷第7期Copyright©博看网. All Rights Reserved.(P O4)6(O H)2]沿胶原纤维有序排列[20]㊂骨缺损修复的关键就在于与骨组织在化学组成和纳米结构上高度相仿的材料的构建,因而仿生矿化技术对口腔颌面骨缺损修复具有重要的指导意义㊂仿生矿化胶原材料模拟了天然骨组织的化学成分和微观结构,使其相比于金属㊁无机非金属及其他有机高分子材料具有明显的优越性[21]㊂仿生矿化胶原材料能够替代缺损骨组织的初始机械强度,且三维多孔结构使其具有优良的骨传导性,也为血管和新生骨组织提供了充足的空间[22-23]㊂从机制层面来说,仿生矿化胶原材料的一些物理化学性质会对成骨相关信号通路产生一定的影响㊂有研究表明,细胞外基质(e x t r a c e l l u l a r m a t r i x,E C M)材料凭借其分层多孔的表面形貌来激活整合素连接激酶/细胞外信号调节激酶1/2(I L K/E R K1/2)和I L K/p38通路,从而介导成骨细胞的分化[24]㊂材料良好的刚性也在细胞行为的调节中起重要作用,刚性的增强可促进巨噬细胞迁移抑制因子(m a c r o p h a g e m i-g r a t i o n i n h i b i t o r y f a c t o r,M I F)的产生,从而激活M I F 介导的A K T/Y A P/R U N X2通路,促进了间充质干细胞向成骨方向的分化[25]㊂除了分层多孔的微观纳米结构和良好的刚性,仿生矿化胶原材料所含的纳米H A晶体可刺激分化早期成骨细胞启动子的甲基化,从而影响碱性磷酸酶(a l k a l i n e p h o s p h a t a s e,A L P)的表达[26]㊂若将成骨相关生物活性因子加载于仿生矿化胶原,则所载物质也可通过激活相应信号通路或上/下调特定的m R N A来增强仿生矿化胶原材料的骨诱导能力㊂3.2仿生矿化胶原材料在G B R中的应用为了规避不可吸收膜二次手术取出的痛苦及膜暴露㊁感染等术后并发症,B i o G i d e ㊁B i o m e n d 和A l-l o D e r m R T M等商业化胶原屏障膜已被开发并逐渐应用于口腔临床G B R术中㊂但纯胶原膜还存在降解速率过快㊁机械性能差和骨诱导能力弱的问题,为了解决这些问题,同时受到天然骨组织组成及结构的启发,越来越多的学者开始着手于仿生矿化胶原膜的研发㊂3.2.1作为屏障膜直接应用在以胶原材料为模板的仿生矿化中,不仅要求成分和组成上的仿生,还要求其微观结构和功能上的仿生㊂与外矿化胶原纤维比较,内矿化的胶原纤维组成的骨组织工程材料在性能上显示出明显的优势,如机械性能增强㊁骨传导性和骨诱导性等促成骨性能改善明显等[27]㊂根据对胶原纤维体外仿生矿化机制的研究可知,胶原纤维内矿化的实现通常需要有机大分子在晶体成核㊁生长过程中发挥重要的调控作用㊂小肠黏膜下层(s m a l l i n t e s t i n a l s u b m u c o s a,S I S)是一种具有良好的生物相容性和生物可降解性的胶原膜,Z HU 等[28]以S I S膜为矿化模板,将具有强大黏附特性的多巴胺(d o p a m i n e,D A)修饰于S I S腹表面并启动D A 辅助的仿生矿化途径㊂吸附在胶原纤维上的D A分子可显著降低胶原纤维与无定形磷酸钙(a m o r p h o u s c a l c i u m p h o s p h a t e,A C P)前体之间的界面能,增强二者之间的润湿作用从而促进矿化早期的胶原纤维内矿化㊂因此,D A诱导S I S膜仿生矿化的机制遵循了界面能引导矿化假说㊂该研究结果显示,用D A对S I S膜进行表面修饰有效促进了H A的快速成核㊁生长,加快了胶原蛋白的矿化速率,并促进了成骨细胞的黏附和增殖㊂为了更高程度地模拟天然骨的微观结构以进一步改善仿生矿化胶原膜的理化性质和促成骨效果, X U A N等[29]制备了一种纳米结构更为有序的分层纤维内矿化胶原(h i e r a r c h i c a l i n t r a f i b r i l l a r l y m i n e r a l-i z e d c o l l a g e n,H I M C)膜㊂体外研究显示,接种于H I M C膜上的B M S C s表现出更强的增殖㊁黏附和成骨分化能力㊂不仅如此,H I M C膜还诱导了巨噬细胞的M2型极化,从而促进了B M S C s的迁移㊂在大鼠颅骨缺损模型的体内研究中,H I M C膜引导了体积更大㊁结构更成熟的新骨形成㊂同时,巨噬细胞极化标志物的免疫组织化学分析结果显示,具有抗炎作用的M2型巨噬细胞在H I M C膜下方骨缺损的修复中发挥着主导作用㊂总的来说,H I M C膜通过高度模拟天然骨的组成和纳米结构,为巨噬细胞的M2型极化和B M S C s的成骨分化提供了良好的免疫微环境,较以往的仿生矿化胶原材料具有更强的成骨诱导能力㊂3.2.2引入活性因子加以修饰并应用3.2.2.1离子功能化许多学者发现一些微量无机离子的掺入可改善仿生矿化胶原材料的性能并有利于骨组织的再生,即离子功能化策略㊂WU等[30]结合以往的许多研究发现,在胶原蛋白基质中掺入锌离子不仅对胶原蛋白降解的过程有良好的调节作用,还可直接影响晶核形成和生长㊂因此,他们将胶原膜与戊二醛-阿仑膦酸钠交联,同时加入掺锌纳米羟基磷灰石(z i n c-d o p e d n a n o-h y d r o x y a p a t i t e,n Z n H A),借此减缓膜材料的降解速率并改善其机械性能及生物相容性㊂仿生矿化胶原材料的离子功能化成功改善了此类生物材料的矿化结构并提高了其促成骨性能,使其在骨缺损修复过程中取得令人满意的治疗效果㊂3.2.2.2加载生长因子4701重庆医学2023年4月第52卷第7期Copyright©博看网. All Rights Reserved.骨组织不仅仅是由胶原纤维和无机矿物质组成,其中还存在一些细胞成分和调节细胞功能的生长因子[31]㊂因此,骨组织再生过程涉及了骨祖细胞㊁E C M 和成骨相关生长因子间复杂的相互作用㊂基于对骨组织生物学的研究,在骨缺损修复材料上引入成骨相关生长因子可提供一个良好的成骨微环境,这是对材料的更高级别的功能仿生㊂骨形态发生蛋白-2(b o n e m o r p h o g e n i c p r o t e i n-2,B M P-2)是最强的骨诱导生长因子之一,在骨缺损修复过程中发挥至关重要的作用[32]㊂有学者利用壳聚糖将B M P-2加载于多孔H A/胶原材料上并使之持续低剂量释放,通过一系列体外及体内实验证实了B M P-2的加载对骨组织的再生有明显的促进作用[33]㊂3.2.2.3加载小分子多肽尽管B M P-2等生长因子被证实在骨缺损修复中发挥优异的成骨诱导作用,但由于大分子活性物质的成本高㊁半衰期短㊁免疫原性较明显及致肿瘤发生等缺点,其临床应用受到严重限制[34]㊂由B M P-2衍生的小分子活性肽不仅具有成本低㊁来源广泛㊁免疫原性小和生物安全性好等优点,还发挥着同样显著的骨诱导作用㊂S U N等[35]利用B M P-2衍生短肽P28对肝素化的矿化S I S膜(m S I S)表面进行修饰,开发了一种用于引导骨质疏松性骨再生的新型G B R膜㊂体外研究显示,将肝素作为固定P28于m S I S上的介质,实现了m S I S/P28中P28的长期缓慢释放,有效促进了去卵巢大鼠的B M S C s(r B M S C s-O V X)的增殖,同时显著上调了r B M S C s-O V X内A L P的活性及成骨相关基因的m R N A表达㊂随后构建了去卵巢大鼠颅骨缺损模型,将m S I S/P28植入并研究其对骨质疏松性骨缺损的影响㊂结果显示,不论是m i c r o-C T还是组织学分析,都证实了m S I S/P28优异的体内骨诱导活性㊂该研究证明,m S I S/P28作为G B R膜在骨质疏松性骨缺损的修复中具有良好的应用前景㊂3.2.2.4加载细胞外囊泡(e x t r a c e l l u a r v e s i c l e s,E V s)E V s内部包含多种蛋白和核酸,在细胞间信号转导中发挥重要作用㊂E V s具有高循环稳定性㊁低免疫原性㊁良好的靶向性及调节受体细胞行为等优势,它们已被广泛研究并应用于组织修复和再生㊂其中, B M S C s分泌的E V s可安全地诱导复杂㊁有效且持久的细胞反应,具有促进干细胞成骨分化和骨组织矿化的功能,还发挥着免疫调节的作用[36]㊂W E I等[37]发现B M S C s成骨分化早期释放的E V s富含A L P,可以在成骨早期阶段进入B M S C s内部并诱导其成骨分化;而B M S C s成骨分化晚期释放的E V s富含钙㊁磷等无机离子,可直接沉积促进胶原蛋白矿化㊂MA 等[38]利用融合肽结构将B M S C s来源的E V s修饰于S I S膜表面,并通过体外研究证明E V s的存在增强了S I S膜对B M S C s增殖㊁迁移及成骨分化的促进作用㊂随后构建了颅骨缺损模型,通过体内研究证明该材料可有效重建骨缺损,证明了E V s修饰的S I S膜是一种非常有前景的G B R膜材料㊂综上所述,由于与天然骨组织高度相似的化学组成和微观结构及其本身所具有的优良性能,仿生矿化胶原材料已逐渐取代生物不可吸收材料而成为骨缺损修复的主流材料㊂此外,仿生矿化胶原材料的优良特性也使其易于加载生物活性物质,创造良好的成骨微环境,从而在临床上取得更好的治疗效果㊂4总结与展望通过仿生矿化的方法对胶原材料进行改进,不仅可获得与天然骨组织高度相似的化学组成和微观结构,还可显著提升其机械强度和骨传导性等性能以符合临床应用的需求㊂在仿生矿化胶原材料表面或内部修饰以成骨相关的生物活性因子,可使其在被植入体内后促进干细胞的黏附㊁增殖和成骨分化,从而表现出明显的骨诱导能力㊂仿生矿化胶原材料是一种功能多样㊁用途广泛的很有前景的生物材料,将为骨组织工程的进步和临床疗效的提升作出巨大贡献㊂参考文献[1]E I N HO R N T A,G E R S T E N F E L D L C.F r a c-t u r e h e a l i n g:m e c h a n i s m s a n d i n t e r v e n t i o n s[J].N a t R e v R h e u m a t o l,2015,11(1):45-54. 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[35]S U N T F,L I U M,Y A O S,e t a l.G u i d e d o s t e o-p o r o t i c b o n e r e g e n e r a t i o n w i t h c o m p o s i t e s c a f-f o l d s o f m i n e r a l i z e d E C M/h e p a r i n m e m b r a n e l o a d e d w i t h B M P-2-r e l a t e d p e p t i d e[J].I n t JN a n o m e d,2018,13:791-804.[36]Y A N G Z Y,L I U X D,Z H A O F J,e t a l.B i o a c-t i v e g l a s s n a n o p a r t i c l e s i n h i b i t o s t e o c l a s t d i f f e r e n-t i a t i o n a n d o s t e o p o r o t i c b o n e l o s s b y a c t i v a t i n g l n-c R N A N R O N e x p r e s s i o n i n t h e e x t r a c e l l u l a r v e s i-c l e s d e r i v e d f r o m b o n e m a r r o w m e s e n c h y m a l s t e mc e l l s[J].B i o m a t e r i a l s,2022,283:121438.[37]W E I Y,S H I M S,Z H A N G J L,e t a l.A u t o l o-g o u s v e r s a t i l e V e s i c l e s-I n c o r p o r a t e d b i o m i m e t i ce x t r a c e l l u l a r m a t r i x i n d u c e s b i o m i n e r a l i z a t i o n[J].A d v F u n c t M a t e r,2020,30(21):2000015.[38]MA S Q,Z H A O Y F,Y A N G Y L,e t a l.A s y m-m e t r i c S I S m e m b r a n e s s p e c i f i c a l l y l o a d e d w i t h e x o s o m e s t h r o u g h t h e m o d i f i c a t i o n o f e n g i-n e e r e d r e c o m b i n a n t p e p t i d e s f o r g u i d e b o n e r e-g e n e r a t i o n[J].C o m p o s i t e s P a r t B-E n g i n e e r i n g, 2022,232:109571.(收稿日期:2022-12-14修回日期:2023-01-21)7701重庆医学2023年4月第52卷第7期Copyright©博看网. All Rights Reserved.。
正十四烷执行质量标准正十四烷是一种重要的烷烃类化合物,常用于润滑油、燃料和化工产品中。
为了确保正十四烷的质量符合国家标准和行业要求,制定和执行质量标准就显得非常重要。
以下是关于正十四烷的执行质量标准的2000字中文文档。
正十四烷执行质量标准一、标准名称:正十四烷执行质量标准二、标准范围:本标准适用于工业生产中的正十四烷产品,主要包括正十四烷的物理性质、化学性质、生产工艺、包装储存和运输等方面。
三、标准依据:本标准参照国家石油化工行业标准和国际上对正十四烷质量的相关标准,结合我国实际情况,综合制定。
四、质量指标:1. 外观与色泽:正十四烷为无色透明液体,不应有机械杂质和悬浮物。
色泽应清澈透明,无异物。
2. 纯度:正十四烷的纯度不低于99.5%,不应含有杂质。
3. 密度:正十四烷的密度应在0.75-0.78g/cm³之间。
4. 沸点范围:正十四烷的初馏点不应低于230°C,终馏点不应高于300°C。
5. 凝固点:正十四烷的凝固点不应低于-20°C。
6. 含硫量:正十四烷的含硫量不应高于10ppm。
5. 包装:正十四烷应采用符合防爆要求的包装容器,严禁混装混载。
六、质量控制:1. 生产过程中应严格按照操作规程操作,严禁未经授权的人员进行操作。
2. 对原材料进行严格检验,确保原材料的质量符合要求。
3. 生产中必须配备相应的安全防护设施,确保生产过程中的安全。
4. 对成品进行全面检测,并留样备查。
5. 严格按照国家相关法律法规要求,对废弃物进行妥善处理,杜绝环境污染。
七、质量检验:1. 对每批生产的正十四烷产品进行物理性质和化学性质的检测,确保符合标准要求。
2. 对包装容器进行抽样检验,确保包装符合要求,不影响产品质量。
3. 对成品进行质量抽检,并对抽检结果进行记录和归档。
八、质量管理体系:1. 建立健全正十四烷产品质量管理体系,明确各个环节的责任和义务。
2. 严格执行质量控制标准,确保产品质量稳定可靠。
578Chapter14Appendix:Manufacturing Composite Laminates14.1Background and OverviewThe multitude of tasks involved in the manufacturing of composite laminates can be categorized into two phases:(1)fabrication and(2)processing.In the fabrication phase thefiber reinforcement and accompanying matrix material are placed or shaped into a structural form such as aflat or curved plate,a cylinder or other body of revolution,and the like.Thefiber and matrix may be in preim-pregnated form,or thefiber and matrix material may be combined for thefirst time during this step of developing the structural form.During the processing phase,heat and pressure are used to densify and consolidate the structure.For thermoset matrices the chemical cross-linking reaction(i.e.,curing)solidifies the structure,whereas thermoplastic matrices become hard after cooling from their melting temperature.Fabrication techniques for composites are not dependent on the type of ma-trix material.In fact,some metal forming techniques have been adapted to com-posites fabrication(e.g.,matched-metal die molding).However,processing con-ditions are entirely dependent on the type of matrix material used.For instance, thermosets require long processing times,whereas thermoplastics require rela-tively high pressures and temperatures.In this appendix we present a brief introduction to the manufacturing of composites by addressing three important areas.First,we discuss fabrication techniques.Next,processing issues are presented.We conclude with a short discussion of manufacturing defects.Overall,we approach the topic of manu-facturing from a general perspective.However,to keep the discussion in the context of this book,we begin by focusing on the manufacture of structural components from layers,or plies,of preimpregnated material,called prepreg. Specifically,layers of material,with thefibers in each layer aligned in a spe-cific direction,are used to form a laminate.We will assume that the laminate579580CHAPTER14.APPENDIX:MANUFACTURING COMPOSITE LAMINATES is fabricated by hand,and we will describe the necessary steps of fabrication. We will further assume that this hand-fabricated laminate will be processedin an autoclave,which is a pressurized oven that provides the proper levels of heat and pressure to solidify and consolidate the structure.In the early yearsof the development offiber-reinforced materials,structural components were fabricated by hand.Even today,in prototype development,hand fabricationis common,and this is also the case for specialty manufacturing and in many university laboratories.However,as labor costs and the need for consistency have increased,engineers have been charged with designing low-cost automated manufacturing techniques.Now,automated techniques like robotic tow and tape placement methods,injection molding,and pultrusion have dramatically reduced the cost of manufacturing some composite ter in the appendix we will consider these various other approaches to fabricating and processing a lam-inate.Common to all manufacturing methods is the use of a die,mold,or man-drel.They provide the structural shape for the composite material,and in this discussion they will be referred to generally as the tool.Tools are usually an inverse,or female,replica of the desired structural shape.The design of the tool is a critical and expensive process.The cost of the tool often far exceeds the material and labor costs to produce a composite structure.Also commonto all manufacturing methods is,as mentioned,the need to apply tempera-ture and pressure to the structural component after thefiber and matrix are brought together into the desired structural form.The pressure takes two forms: actual pressure,ideally hydrostatic,to consolidate the tows and layers;a vac-uum to remove air entrapped between the layers and to reduce the amount of unwanted gases given offby the resin as it cures.The application of pressure can be in the form of closing both halves of the tool or,as with aflat struc-tural component,pressing the laminate in a hot press.More commonly,how-ever,and as will be assumed here,pressure is applied by putting the uncured structural component into an autoclave.Finally,the vacuum requirement is metby enclosing the structural component in a vacuum-tight bag and drawing a vacuum.14.2Fabrication14.2.1Tooling and Specialty MaterialsToolingAs all fabrication methods require tools to provide the shape of the compos-ite structure during processing,the design and construction of the tool are critical components of the manufacturing process.Because the tool is heated and pressurized,especially critical is the choice of tooling material.Factors which must be considered in tool material selection are dimensional stability and compatibility,cost,surfacefinish,and durability.Table A.1lists the co-efficients of thermal expansion for several tool materials.Of the metals,tool14.2.FABRICATION581 TABLE14.1Thermal expansion of tooling materialsMaterial system Coefficient of thermal expansion(×10–6/°C)Polymer matrix composites (fiber dir., 1)• Aramid or graphite-reinforced• Boron fiber-reinforced• Glass fiber-reinforcedαSlip cast and fired ceramic 0.83 Tool steel11.1 Electroformed iron11.7 Electroformed nickel12.8PlasterHigh-temperature epoxy Aluminum13.919.423.3−1.5 to 1.1 2.3 to 3.0 6.3 to 8.4steel most closely matches that of the composites.Steel tools are also highly durable and have good thermal conductivity;however,they are extremely heavy and they take substantial time to heat and cool.Ceramic tools have the low-est thermal expansion,so their dimensional stability is the best,and they also have a thermal conductivity close to that of tool steels.However,they are brit-tle and must be protected from chipping and cracking.Sometimes ceramic in-serts are used in steel tools to combine the best characteristics of both materi-als.Aluminum tools are easily machined and less expensive than steel or ceramic. They are lighter than steel tools and they heat and cool faster than steel;however, they are not as durable as steel tools and their thermal expansion is excessive. Plaster tools are sometimes used when durability is not required.They can be made easily by pouring the uncured plaster around a model.Once the plaster has been cast,it is cured and then hardened by coating with a varnish.Actually, graphite-or glass-reinforced composite materials can be used to fabricate a tool. If this is the case the thermal expansion of the tool can be exactly matched to that of the composite posite tools are durable,their surfacefinish is excellent,and they are less expensive than steel tools.However,they usually require that a plaster casting be made of the structurefirst.Specialty materialsMany secondary or specialty materials are used in composites manufacturing. Before we discuss the various types of specialty materials it is helpful to exam-ine a typical lay-up of a composite structure prepared for autoclave processing. Figure A.1shows a cross section of an autoclave specimen.In addition to the actual composite laminate,there are release coatings,peel plies,releasefilm, bleeder plies,breather plies,vacuum bags,sealant tape,and damming material. Each of these materials serves a specific function.For instance,release agents are used to prevent the composite material from bonding to the tool.The il-lustration in Figure A.1is based on processing aflat laminate,and thus the582CHAPTER14.APPENDIX:MANUFACTURING COMPOSITE LAMINATES portionF IG U R E A .1T y p i c a l a u t o c l a v e l a y -u pS t a V a c u u m b a g g i n g f i l m S a c r i f i c i a l p l y (o p t i o n a l )P e e l p l y C o m p o s i t e l a m i n a t eP e e l p l yP o r o u s r e l e a s e f i l m B l e e d e r p l i e sP o r o u s r e l e a s e f i l mB r e a t h e r p l i e s T o p c a u l p l a t e (o p t i o n a l )B r e a t h e r p l i e sR e l e a s e c o a t /f i l mT o o l (f l a t p l a t e )583584CHAPTER14.APPENDIX:MANUFACTURING COMPOSITE LAMINATES TABLE14.2Mold release agentsFilms or dispersions Coated paper, extruded filmLiquids, resins, greases Teflon (tetrafluoroethylene), Tedlar (polyvinylfluoride) Polyvinyl alcohol (PV A), polyamines, polyethylene, cellophaneSilicone polymersType Form Examples FluorocarbonsPolymer filmsSiliconesPaste Parafin, carnuba,microcrystalline waxes WaxesLiquids or particles (external and internal release agents)Stearic acids (calcium, zinc, lead, aluminum, magnesium salts)Metal saltsPowders Talcum, micaInorganiccompoundsof the tool at the bottom of thefigure is actually aflat plate and the portion of the tool toward the top is also aflat plate,sometimes called a caul plate when used in this fashion.However,it is easy to imagine the bottom and top tool components having curvature,or only a curved bottom plate being present and the peel plies,releasefilm,and so on,being draped over the curved uncured laminate.Release agentsRelease agents are used to coat the tool so that the composite structure is pre-vented from bonding to the surface.They are usually a paste or liquid that is coated onto the tool surface and allowed to dry.Films are also used,but they are limited toflat or single-curvature surfaces.Table A.2lists several types of release agents that are used.1.Fluorocarbons.Fluorocarbon polymers are used extensively in autoclavemolding.Tedlar R,a polyvinylfluoride,is afluorocarbonfilm manufactured by DuPont.FEP(fluoroethylene propylene)forms a continuousfilm on the mold surface and is used for composites cured up to177◦C.Above this temperature thefluorine disassociates from the polymer.PTFE(polyte-trafluoroethylene),a polymeric dispersion of Teflon R,is stable up to260◦C.2.Polymerfilms.These polymers are insoluble in most solvents,so they areapplied as extruded or blownfilms.PVA(polyvinyl alcohol),cellophane, polyamines,and polyethylene have all been used as release agents.3.Silicones.The commercial silicones are cured polymers with high meltingpoints and low volatility.They are applied in liquid form or as a grease.14.2.FABRICATION585Some special silicone release agents are stable up to480◦C;however,most are limited to about200◦C.4.Waxes.Carnuba paste wax is cheap and easily applied.It is sometimespolished before the composite is laid onto the tool surface.Carnuba waxes are excellent mold release agents for composites cured below250◦F.Above this temperature the wax begins to degrade.5.Metal salts.Stearic acid,a fatty acid,is used widely for mold release.It hasa sharply defined melting point at71.5◦C and has good wetting properties.The main derivatives of stearic acid(such as calcium,zinc,and lead salts) are also used as release agents.The choice of metallic stearate to use for a specific application depends primarily on the type of polymer matrix.6.Inorganic compounds.These are probably the oldest known release agents.Because they are insoluble,they are applied as powders.Talcum and mica are the most common compounds used.In some cases they are mixed with metal stearates to improve their release ability.Peel plies and releasefilms and fabricsSurfaces are protected from contamination by peel plies,and they are normally removed from the composite structure just before bonding or secondary coating operations.The most common peel plies are heat-cleaned-and-scoured nylon, heat-cleaned lightweightfiberglass,or polyester er preference of the surface texture after the removal of the peel ply dictates the choice of a specific type.Releasefilms and fabrics serve many different purposes.Sometimes they are used as separators between successive layers of preimpregnated material, and they are also used to separate the bleeder or breather materials from the composite laminate.They are most commonly a Teflon-coatedfiberglass fabric, and in some cases the releasefilm is porous so that resin canflow through the film.For example,porous releasefilms are used to separate the bleeder plies from the composite laminate.This allows the resin toflow from the laminate through the releasefilm and into the bleeder plies.Bleeder and breather pliesBleeder and breather plies are porous,high-temperature fabrics which are used to absorb excess resin during processing.Most preimpregnated materials are supplied with excess resin,which is subsequently removed during processing. The resin is removed to increase thefiber volume fraction andflush voids from the laminate.The excess resin is trapped and absorbed by the porous bleeder plies.Fiberglass,cellulose,and polyester fabrics are all used as bleeder plies.Breather plies are used to provide a vacuum pathway into the composite laminate,and they also act as a conduit for the removal of volatiles during cure. They must remain porous at high temperatures and pressures.Most bleeder586CHAPTER14.APPENDIX:MANUFACTURING COMPOSITE LAMINATES materials can also be used as breather plies.In addition,perforatedfluorocarbonor nylonfilms and Teflon-coatedfiberglass are sometimes used.BaggingfilmsBaggingfilms form a barrier between the composite laminate and the oven or autoclave environment.The baggingfilm is sealed around the edge of the lay-upby sealant tape,and thefilm is drawn down onto the composite laminate by pulling a vacuum under the bag.Vacuum bags must be heat resistant,flexible, nonvolatile,and resistant to tearing.Several high-temperature polymerfilms are used,including Kapton R(up to316◦C),nylon(180◦C),and PVA(121◦C). Silicon rubber bags are also used up to about200◦C,and they have the added advantage of being reusable.14.2.2Hand Lay-upEven though the method has been replaced with automated techniques,the lay-up of preimpregnated material by hand is the oldest and most common fabrica-tion method for advanced composite structures.Furthermore,the basic featuresof the method remain unchanged.A pictorial essay showing each step in the hand lay-up of aflat composite laminate is shown in Figures A.2–A.15.Each step must follow in successive fashion in order to obtain a high-quality composite laminate afterfinal processing.A description of these steps follows.Step1,Figure A.2The surface of the tool is cleaned and a release agent is applied.If the surfaceis not clean,then the release agent will not function properly.The release agent can be in liquid form,or it may be a solidfilm.(In the photo-essay,to provide an indication of scale,a hand-held pointer or knife is included in the photographs.) Step2,not shownAn optional sacrificial layer is laid up on the tool surface.This layer is usuallyafiberglass fabric made with the same resin system as the composite laminate. The sacrificial layer protects the laminate from surface abrasion and surface irregularities during manufacturing.Step3,Figure A.3A peel ply is placed on top of the sacrificial layer.The peel ply will be removed after processing.Step4,Figure A.4The preimpregnated plies are cut according to design specifications.They can be cut by hand using shears or a steel blade knife.However,automated cutting ma-14.2.FABRICATION587 chines have largely replaced hand cutting.The Gerber knife is a reciprocating-knife system originally developed for the textile industry.It is extremely fast and can cut up to20plies at one sers have been used for cutting, but they are expensive and have limitations on the number of plies that can be cut at one time.Water-jet cutters are also used extensively,and they can cut a large number of plies(>40)at one time,but some moisture absorp-tion occurs during the cutting operation.Ultrasonic cutters have been used as well.Step5,Figures A.5,A.6Thefirst prepreg ply is oriented and placed upon the tool or mold.Subsequent plies are placed one upon another;a roller or other small hand tool is used to compact the plies and remove entrapped air that could later lead to voids or layer separations.It is important that the preimpregnated material have sufficient tack so that it sticks slightly to the peel ply and to the adjacent plies.Tackiness,a characteristic of preimpregnated material,quantifies the relative stickiness of the plies at room temperature.As the preimpregnated material ages,its tackiness is reduced.Eventually,the plies no longer stick together and they may have to be heated slightly to soften them during lay-up.Oils and dirt on the surface of the preimpregnated plies will contribute to reducing composite strength after processing.Technicians should wear gloves during lay-up so that oils and dirt from the hands do not contaminate the prepreg plies during lay-up.In some cases the hand lay-up procedure may be carried out in a clean room to reduce the risk of contamination of the prepreg plies.Step6,Figure A.7Aflexible resin dam is anchored to the sacrificial layer approximately3mm from the edge of the laminate.The dam prevents resinflow out of the laminate,in the plane of the laminate.Flexible dams can be made from silicon rubber,cork,or release coated metal.(As no sacrificial layer is being used in the procedure here, theflexible dam is anchored to the peel ply.)Step7,Figure A.8Another peel ply is placed on top of the laminate to protect the laminate surface.Step8,not shownA sheet of porous releasefilm is laid over the dam and the laminate.The porous releasefilm will serve as a barrier to prevent bonding of the composite laminate to the secondary materials to follow.588CHAPTER14.APPENDIX:MANUFACTURING COMPOSITE LAMINATES Step9,Figure A.9Next,bleeder plies are laid up over the releasefilm,in this case the peel ply.The bleeder plies extend to the edge of the laminate.The number of bleeder pliesto be used for a given laminate can be determined by using a resinflow process model or through empirical observation.As the number of bleeder plies increases, thefinalfiber volume fraction of the composite laminate increases.Eventually,a maximum number of bleeder plies is reached and no further increase infiber volume fraction occurs.Step10,not shownAnother porous release ply is next laid up over the bleeder plies extending past theflexible dam.This prevents excessive resinflow into the breather material while maintaining a vacuum pathway into the composite laminate.Step11,not shownBreather plies are placed over the entire lay-up.The breather plies will con-duct the vacuum path into the laminate.It is critically important that sufficient breather material is used throughout the entire laminate.Creases and areas with shallow curvature are sometimes reinforced with additional layers of breather ma-terial to ensure that the breather plies do not collapse in these ually, two or three breather plies are sufficient.Step12,not shownAn edge bleeder is used to connect to the vacuum ports.An edge bleeder is nothing more than a strip of breather material folded along its length several times.It is placed so that it overlays the breather material surrounding the laminate and extends out to a convenient location for the placement of the vacuum port.Step13,Figure A.10Caul plates are sometimes placed on top of the lay-up.The caul plate is a steelor aluminum plate that protects the surface from sharp temperature increases (it acts as a heat sink)and it gives a smooth nonwavy surface texture.Step14,Figure A.11If a caul plate is used,then additional breather or bleeder plies are placed over the plate to protect the vacuum bag from puncture.Step15,Figure A.12Sealant tape is placed around the entire periphery of the lay-up.14.2.FABRICATION589 Step16,Figure A.12The vacuum bag is cut to size and placed over the lay-up.Step17,Figure A.13The bag is sealed by pressing the bag over the sealant tape.It is critically impor-tant to ensure that the bag is adequately sealed before proceeding to the process-ing cycle.Many parts are scrapped because the vacuum fails during processing, causing excessive voids,inadequate resinflow,or incomplete consolidation. Step18,Figures A.14and A.15The vacuum port is installed through the bag and the contents are evacuated. The bag is now checked for leaks.If any are detected,they are repaired before ually a leak test calls for application of a vacuum to some specified level(cm of Hg),followed by a30–60minute hold.During the hold the bag is disconnected from the vacuum source and the pressure level within the bag is monitored.If the bag is sealed well and there are no leaks,then the vacuum level should not change for the30–60minutes.Some leaking generally occurs,so it is a question of having sufficient vacuum pump capacity to maintain the specified vacuum level.When the vacuum is satisfactory,the composite part is ready for processing.The specific processing steps depend on the particular composite material being used,and the operation of the autoclave depends on the specific make and model.General discussions of processing and autoclave features are presented in the sections to follow.Obviously,there is a significant amount of skilled labor necessary for the hand lay-up of composite parts.Each step has a specific purpose and function. This type of fabrication is the most time-consuming,but it is also the most flexible and when combined with autoclave processing,it results in high-quality parts.Automated equipment can be used to cut and place the preimpregnated material onto the tool surface.The economics of manufacturing dictate that a relatively large volume of parts must be made to make automated equipment cost-effective.Some of these automated methods will be discussed later.590CHAPTER14.APPENDIX:MANUFACTURING COMPOSITE LAMINATESRelease filmMold surfaceFIGURE14.2Step1in the hand lay-up method:The mold is covered with a releasefilm.Peel plyRelease filmFIGURE14.3Step3in the hand lay-up method:A peel ply is laid on top of releasefilm.No sacrificial layer is used in the example lay-up.14.2.FABRICATION 591PrepregCutting bladeStraight edgeFIGURE 14.4Step 4in the hand lay-up method:The prepreg plies are cut to design specifications.Prepreg plies laid onto mold surfacePrepreg ply with backing paperFIGURE 14.5Step 5in the hand lay-up method:The prepreg plies are oriented and laid on the tool surface.592CHAPTER14.APPENDIX:MANUFACTURING COMPOSITE LAMINATESPeel ply Prepreg lay-upRollerMold surfaceFIGURE14.6Step5(continued)in the hand lay-up method:The prepreg plies are rolled out to remove wrinkles and air bubbles trapped during lay-up.Flexible resin damMold surfacePrepreg lay-upFIGURE14.7Step6in the hand lay-up method:Aflexible resin dam is placed around the edge of the laminate.The dam prevents resinflow in the plane of the laminate.14.2.FABRICATION 593Peel plyPrepreg lay-upFIGURE14.8Step7in the hand lay-up method:Another peel ply is placed on top of the laminate to protect the laminate surface.Bleeder pliesPeel plyFIGURE14.9Step9in the hand lay-up method:Bleeder plies are cut and placed on top of the lay-up to absorb excess resin.Note:No porous releasefilm was used in the example lay-up.The peel ply serves as a releasefilm in this case.594CHAPTER14.APPENDIX:MANUFACTURING COMPOSITE LAMINATESBottom mold Lay-upTop caul plateFIGURE14.10Step13in the hand lay-up method:A caul plate is placed on top of the lay-up.Bleeder and breather plies can be seen directly underneath the caul plate.Breather pliesMold and lay-upFIGURE14.11Step14in the hand lay-up method:Additional breather plies are wrapped around the entire lay-up to protect the vacuum bag from puncture and to provide a vacuum pathway into the laminate.14.2.FABRICATION 595Vacuum bagSealant tape FIGURE14.12Steps15and16in the hand lay-up method:Sealant tape is placed around the periphery of the lay-up,and a vacuum bag is cut to size to cover the lay-up.Sealed vacuum bagFIGURE14.13Step17in the hand lay-up method:The bag is sealed by pressing the bag over the sealant tape.596CHAPTER14.APPENDIX:MANUFACTURING COMPOSITE LAMINATESRubber gasket Vacuum portVacuum port baseFIGURE14.14Step18in the hand lay-up method:A vacuum port is installed through the vacuum bag.AutoclaveVacuum linesFIGURE14.15Finished lay-up after vacuum has been applied ready for au-toclave processing.14.3.PROCESSING 59714.3Processing 14.3.1Overall ConsiderationsOnce the matrix and fibers are combined,and they have the desired structural shape,it is necessary to apply the proper temperature and pressure for specific periods of time to produce the fiber-reinforced structure.A judicious choice of temperature,pressure,and time produces composites that are fully cured,com-pacted,and of high quality.Slight deviations from the recommended processing conditions can result in unacceptable quality.The temperature cycle is usually referred to as the cure cycle,as it is the heating of the resin that initiates the cure reaction.The overall cycle,which includes pressurization and the temperature cycle,is referred to as the process cycle.The typical cure cycle for thermosetting polymer matrix composites is a two-step cycle shown in Figure A.16.In such cycles the temperature of the material is increased from room temperature to some elevated temperature,and this temperature is held constant for the first dwell period.Afterwards,the temperature is increased again to a second temperature and held constant for the second dwell period.After the second dwell,the part is cooled to room temperature at a constant rate.Because there are two dwell periods,this type of cure cycle is referred to as a two-step cure cycle.The purpose of the first dwell is to allow gases (entrapped air,water vapor,or volatiles)to escape from the matrix material and to allow the matrix to flow,facilitating compaction of the part.Thus,the viscosity must be low during the first dwell.Typical viscosity versus temperature profiles of polymer matrices show that as the temperature is increased,the viscosity of the polymer decreases until a minimum viscosity is reached.As the temperature is increased further,the polymer begins to cure rapidly and the viscosity increases dramatically.Thus,the first dwell temperature must be chosen judiciously to allow the viscosity of the resin to be low,while keeping the cure to a minimum.Isothermal viscosity versus time profiles of the resins involved are useful in determining pot life,namely,the maximum length of time at a specific temperature for the resin to remain fluidlike.The first dwellTimeT e m p e r a t u r e FIGURE 14.16Typical two-step cure cycle598CHAPTER 14.APPENDIX:MANUFACTURING COMPOSITE LAMINATES time must be less than the pot life of the polymer at the dwell temperature.The purpose of the second dwell is to allow cross-linking of the resin to take place.Here the strength and related mechanical properties of the composite are developed.What is important to realize is that the cross-linking,or curing,process gives offheat (i.e.,it is exothermic).Thus,temperatures can increase during cure even with no heat being added.However,since curing is acceler-ated by supplying heat,care must be taken not to overheat the composite by a combination of the exothermic nature of cure and the heat added to speed up the process.To characterize the exothermic cross-linking reaction of a ther-mosetting polymer matrix,a thermal cure monitor technique such as isothermal differential scanning calorimetry (DSC)is commonly used.Figure A.17shows a typical isothermal DSC trace for a thermosetting polymer.The resin releases energy as the exothermic cross-linking reaction proceeds.Eventually,the DSC trace approaches a flat line as the cross-linking reaction nears completion.If the applied temperature,T ,is increased,the reaction rate increases and the time to complete the reaction decreases.If the applied temperature is decreased,the reaction rate decreases and the time to complete the reaction increases.Several competing priorities take place in the choice of the second dwell temperature.First,a low temperature is desirable to ease manufacturing and to reduce thermally induced stresses at the micromechanics level that are a result of the mismatch in the coefficients of thermal expansion between the fiber and matrix,and at the layer level that are a result of the mismatch in coefficients of expansion between layers with different fiber orientations.Second,the process-ing time should be as short as possible for economic considerations.Because low temperatures require longer dwell times,these two concerns must be compro-mised.Third,however,the temperatures due to the exothermic nature of curing must be kept in check.Often a vacuum is applied to the part during processing,typically during the first dwell to help facilitate removal of entrapped gases.Vac-EndothermicH e a t f l o w ExothermicTimeFIGURE 14.17Typical isothermal DSC relations for a polymer resin:Applied temperature T 1>applied temperature T 2。