Introduction to polymer science

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1 Introduction to polymer science
Thermoset Resin 热固性树脂 四川大学化学学院

2 Thermosetting plastics
Thermosetting plastics (thermosets) are polymer materials that irreversibly cure. The cure may be done through heat (generally above 200oC), through a chemical reaction (two-part epoxy, for example), or irradiation such as electron beam processing. Most often, the cure process involves cross-linking which strengthens the polymer (setting). Thermoset materials are usually liquid or malleable prior to curing and designed to be molded into their final form, or used as adhesives. Others are solids like that of the molding compound used in semiconductors and integrated circuits.

3 Thermosetting plastics
Cross-linked molecules Cooled Heated softens Permanently hard Thermosetting means the plastic softens when initially heated , but sets permanently rigid once it has cooled or has been chemically It is similar to the relationship between a raw and a cooked egg.

4 Preparation Strategy of thermosets
Multi functional monomer to crosslinked polymer Melamine resin Polyester resin + Prepolymer to crosslinked polymer Phenolic resin Urea resin

5 Phenolic resin In 1872，the famous Germany chemist, Adolf von Bayer had already observed the residue at the bottom of the test tube using for the reaction of Phenol and formaldehyde, which was very hard to get rid of. However, his interesting was focused on the organic dye, he didn’t research this reaction Dr. Leo Baekeland First totally synthetic plastic (1907) Patented in 1909 By controlling the pressure and temperature applied to phenol and formaldehyde, he found he could produce his dreamed-of hard moldable plastic: bakelite Replaced rubber for insulation in electrics Dr. Leo H. Baekeland

6 Phenolic resin

7 Properties of Phenolic resin
高温性能 酚醛树脂最重要的特征就是耐高温性，即使在非常高的温度下，也能保持其结构的整 体性和尺寸的稳定性。 粘结强度 酚醛树脂一个重要的应用就是作为粘结剂。酚醛树脂是一种多功能，与各种各样的有 机和无机填料都能相容的物质。润湿速度特别快，并且在交联后可以为磨具、耐火材料， 摩擦材料以及电木粉提供所需要的机械强度，耐热性能和电性能。 高残碳率 在温度大约为1000℃ 的惰性气体条件下，酚醛树脂会产生很高的残碳，这有利于维持 酚醛树脂的结构稳定性。也是它能用于耐火材料领域的一个重要原因。 低烟低毒 与其他树脂系统相比，酚醛树脂具有低烟低毒的优势。在燃烧的情况下酚醛树脂系统 将会缓慢分解产生氢气、碳氢化合物、水蒸气和碳氧化物。分解过程中所产生的烟相对 少，毒性也相对低。 抗化学性 交联后的酚醛树脂可以抵制大多化学物质的分解。例如汽油，石油，醇，乙二醇和各 种碳氢化合物。

8 Application of Phenolic resin

9 Application of Phenolic resin
酚醛树脂主要应用于电绝缘体铸件，用于电器外壳、设备和汽车的部件等。也有部分用于木材层板的粘合剂，用于家具和室内装修。通过浸渍木材和纸板得到的装饰薄板可用于工作台面、印刷电路、墙面装饰等。

10 Urea formaldehyde resin
Urea-formaldehyde, also known as urea-methanal, named so for its common synthesis pathway and overall structure, is a non-transparent thermosetting resin or plastic, made from urea and formaldehyde heated in the presence of a mild base such as ammonia or pyridine. These resins are used in adhesives, finishes, MDF, and molded objects. C NH2 H2N O NH CH2 HO CH2O ( ) n N Catalyst -H2O Prepolymer Curing

11 Properties of Urea formaldehyde resin
1924年，英国氰氨公司研制出脲醛树脂，1928年始出售产品，30年代中期产 量达千吨，80年代世界年产量已超过1.5Mt。 脲醛树脂成本低廉，颜色浅，硬度高，耐油，抗霉，有一定的绝缘性和耐温性， 是开发较早的热固性树脂之一。 脲醛树脂坚硬，耐刮伤，耐弱酸弱碱及油脂等介质，价格便宜，具有一定的韧 性，但它易于吸水，因而耐水性和电性能较差，耐热性也不高。 脲醛树脂可用于耐水性和介电性能要求不高的制品，如插线板、开关、机器手 柄、仪表外壳、旋纽、日用品、装饰品、麻将牌、便桶盖，也可用于部分餐具 的制造。 脲醛树脂是国内外木材工业的主要粘合剂。由于它胶合强度高、固化快、操作 性好、生产成本低、原料丰富易得等一系列优点而得到广泛应用。但是脲醛树 脂所含的游离甲醛具有毒性，树脂中的游离甲醛含量越低，其毒性就越小。

12 Application of Urea formaldehyde resin

13 Melamine formaldehyde resin
Thermosetting resins of the amino resin family, made by reacting melamine with formaldehyde. The lower molecular weight, uncured melamine resins are water soluble used for impregnating or laminating. Glass fiber reinforced melamine can be processed by compression molding. Also known as MELAMINE PLASTICS or MELAMINE RESINS.

14 Properties of melamine formaldehyde resin
蜜胺树脂（三聚氰胺甲醛树脂）单体具有较大的化学活性，很高的胶接强度， 耐水能力高，能经历三小时以上的沸水，热稳定性高，耐磨性好，固化快。 蜜胺树脂成品比脲醛树脂成品硬度和耐磨性好，对化学药物的抵抗能力，电绝 缘性能等都好。但是固化后胶层容易破裂不宜单独使用。 储存期短，易变质，制成粉状可延长储存期限。 蜜胺树脂加无机填料后制成模塑制品，色 彩丰富，大多用于装饰板、餐具、日用品。 餐具外观酷似瓷器或象牙，不易脆裂又适 宜机械洗涤。 蜜胺树脂与脲醛树脂混合可配制成胶粘剂， 用于制造层压材料。用丁醇改性的密胺树 脂可作涂料和热固性漆。

15 Application of melamine formaldehyde resin

16 Polyester resin Polyester resin, also known as alkyd resin, are resin formed by the reaction of polyols (also known as polyhydric alcohols, organic compounds with multiple alcohol or hydroxy functional groups) and polycarboxylic. the term alk-yd from "alcohol and acid or anhydride. Typical polyols used are glycols such as ethylene glycol. The usual polycarboxylic acids used are unsaturated carboxylic acid such as phthalic acid, maleic acid, oleic acid. Water, which is a by-product of this esterification reaction, is removed from the reaction mass as soon as it is formed to drive the reaction to completion. the unsaturated groups react with oxygen from the air, causing the oils to crosslink and harden.

17 Glyptal resin C O HOCH2 CH2 CH2OH OH OCH2 CH2O ( ) + Prepolymer
在适当的温度条件下，甘油的两个伯羟基先与二酸反应得到的线性预聚物，而 当温度升高后，预聚物中残留的仲羟基将继续发生反应将线形的分子链交联。

18 Unsaturated polyester
C O R OH HO CH ( ) n -H2O CH2 Ph + prepolymer ( ) m ( ) m ( ) m Unsaturated polyester resins may be obtained by polymerization of unsaturated acids (e.g., maleic anhydride) with a diol such as propylene glycol or diethylene glycol. Corporation of the saturated acid serves to decrease crosslink density and consequently resin brittleness. Fumaric acid may be used in place of maleic acid to increase impact resistance. The low-molecular-weight prepolymer is soluble in styrene, which can then participate in a crosslinking step with the double bonds of the prepolymer during initiation by peroxides.

19 Properties of unsaturated polyester resin
工艺性能优良。这是不饱和聚酯树脂最大的优点。可以在室温下固化，常压下 成型，工艺性能灵活，特别适合大型和现场制造玻璃钢制品。 固化后树脂综合性能好。力学性能指标略低于环氧树脂，但优于酚醛树脂。耐 腐蚀性，电性能和阻燃性可以通过选择适当牌号的树脂来满足要求，树脂颜色 浅，可以制成透明制品。 品种多，适应广泛，价格较低。 缺点是固化时收缩率较大，贮存期限短，含苯乙烯，有刺激性气体，长期接触 对身体健康不利。 聚酯树脂主要用于胶粘玻璃钢、硬质塑料、混凝土、电气罐封等。

20 Application of unsaturated polyester resin
FRP (Fiberglass Reinforced Plastics 亦 称作GRP，Glass Reinforced Plastics， 或Glass fibre reinforced plastics (GFRP) 即纤维强化塑料，一般指用玻璃纤维增 强不饱和聚脂、环氧树脂与酚醛树脂基 体。 最为广泛使用的醇酸树脂是玻纤增强的 不饱和聚酯树脂，是热固性树脂中用量 最大的，也是玻璃钢复合材料制品生产 中用得最多的树脂。虽然隶属于醇酸树 脂，但是因为多用途和高使用量，已经 发展成为一个单独的行业。

21 Application of unsaturated polyester resin

22 Epoxy resin Epoxy or polyepoxide is a thermosetting polymer formed from reaction of an epoxide “prepolymer" with polyamine or cyclic anhydride as "hardener". Epoxy has a wide range of applications, including fiber-reinforced plastic materials and general purpose adhesives. Reactive sites, Adhesion, and Wetability High temperature performance and Rigidity Toughness Reactive sites Toughness Structure of unmodified bisphenol-A epoxy prepolymer. n denotes the number of polymerized subunits and is in the range from 0 to about 25.

23 Curing agent of epoxy resin
常用环氧树脂固化剂有 胺类固化剂 包括脂肪胺、脂环胺、芳香胺等 酸酐类固化剂 低分子量聚酰胺类固化剂 咪唑类固化剂 三级胺类固化剂 常温或低温固化一般选用胺类固化剂，加温固化则常用酸酐、芳香类固化剂。 环氧种类 产量比例 % 双酚A 81 溴化环氧 13 酚醛环氧 3 脂肪族环氧 1 其它 2 R NH2 H2N C O R NH C O ( ) n R N R N

24 Curing of epoxy resin polyamine as "hardener"
Maleic anhydride as "hardener"

25 Properties of epoxy resin
形式多样。各种基体、固化剂、改性剂体系几乎可以适应各种应用对形式提出的要求，其范围可 以从极低的粘度到高熔点固体。 固化方便。选用各种不同的固化剂，环氧树脂体系几乎可以在0～180℃温度范围内固化。 粘附力强。环氧树脂分子链中固有的极性羟基和醚键的存在，使其对各种物质具有很高的粘附力 。环氧树脂固化时的收缩性低，产生的内应力小，这也有助于提高粘附强度。 收缩性低。环氧树脂和所用的固化剂的反应是通过直接加成反应或树脂分子中环氧基的开环聚合 反应来进行的，没有水或其它挥发性副产物放出。它们和不饱和聚酯树脂、酚醛树脂相比，在固 化过程中显示出很低的收缩性（小于2%）。 力学性能。固化后的环氧树脂体系具有优良的力学性能。 电性能。固化后的环氧树脂体系是一种具有高介电性能、耐表面漏电、耐电弧的优良绝缘材料。 化学稳定性。通常，固化后的环氧树脂体系具有优良的耐碱性、耐酸性和耐溶剂性。像固化环氧 体系的其它性能一样，化学稳定性也取决于所选用的树脂和固化剂。适当地选用环氧树脂和固化 剂，可以使其具有特殊的化学稳定性能。 尺寸稳定性。上述的许多性能的综合，使环氧树脂体系具有突出的尺寸稳定性和耐久性。 耐霉菌。固化的环氧树脂体系耐大多数霉菌，可以在苛刻的热带条件下使用。

26 Application of epoxy resin

27 Silicon resin Silicone resins are a type of silicone material which is formed by branched, cage-like oligosiloxanes with the general formula of Rn-Si-Xm-Oy, where R is a non reactive substituent, usually Me or Ph, and X is a functional group H, OH, Cl or OR. These groups are further condensed in many applications, to give highly crosslinked, insoluble polysiloxane networks Silicone resins are prepared by hydrolytic condensation of various silicone precursors. In early processes of preparation of silicone resins sodium silicate and various chlorosilanes were used as starting materials.

28 Preparation of silicon resin
Cl Si R H2O -HCl HO OH O ( ) n -H2O Linear Cl Si R H2O -HCl + HO OH -H2O O ( ) n m Crosslinked R = CH3, C2H5, Ph, H, etc…

29 Properties of Silicon resin
热稳定性。硅树脂的 Si-O 键有较高的键能（363kJ/mol），所以比较稳定，耐热性和耐 高温性能均很高。一般说来其热稳定性范围可达200～250℃，特殊类型的树脂可以更高 一些。 力学性能。硅树脂固化后的力学性能不高，若在大分子主链上引进氯代苯基，可提高力 学性能。硅树脂玻璃纤维层压板的层间粘接强度较差，受热时弯曲强度有较大幅度的下 降。若在主链中引入亚苯基，可提高刚性、强度及使用温度。 电性能。硅树脂具有优良的电绝缘性能，它的击穿强度、耐高压电弧及电火花性能均较 优异。受电弧及电火花作用时，树脂即使裂解而除去有机基团，表面剩下的二氧化硅同 样具有良好的介电性能。 憎水性。硅树脂的吸水性很低，水珠在其表面只能滚落而不能润湿。因此，在潮湿的环 境条件下，有机硅树脂玻璃纤维增强复合材料仍能保持其优良的性能。 耐腐蚀性能。硅树脂玻璃纤维增强复合材料可而浓度（质量）10%～30%硫酸、10%盐 酸、10%～15%氢氧化钠、2%碳酸钠及3%过氧化氢。醇类、脂肪烃和润滑油对它的影 响较小，但耐浓硫酸及某些溶剂（如四氯化碳、丙酮和甲苯）的能力较差。

30 Application of silicon resin

31 Urethane resin + HO R OH N R’ C O n NH [ ]
A polyurethane, IUPAC abbreviation PUR, but commonly abbreviated PU, is any polymer consisting of a chain of organic units joined by urethane (carbamate) links (-O-CO-NH-). Polyurethane polymers are formed through step-growth polymerization by reacting a monomer containing at least two isocyanate functional groups with another monomer containing at least two hydroxyl (alcohol) groups in the presence of a catalyst. Reaction of multi-functional monomers (number of functional group of the monomer ≥ 3) will result in a cross-linked urethane resin. HO R OH N R’ C O + n NH [ ] polyurethane

32 Diisocyanate NCO CH3 Aromatic diisocyanate NCO CH2 OCN NCO OCN
toluene diisocyanate (TDI) diphenylmethane diisocyanate (MDI) p-phenylene diisocyante (PPDI) NCO NCO OCN CH3 H3C naphthalene diisocyanate (NDI) o-tolidine diisocyanate (TODI). NCO OCN (CH2)6 NCO OCN Aliphatic diisocyanate hexamethylene diisocyanate (HDI) cyclohexane diisocyanate (CHDI)

33 Polyol Bi-functional CH2CH2 OH HO (CH2)3 HO O OH CH2CH2 OH O H ( )
Glycol Dipropylene glycol Polyethylene glycol Tri-functional CH2 OH HO C CH2OH CH3 CH2 OH HO CH Glycerin Tri-hydroxymethyl propane Tetra-functional NH2 H2N CH3 CH2 OH HO C CH2OH Toluenediamine Pentaerythritol Penta-functional: xylitol (木糖醇) Hexa-functional: sorbitol (山梨醇), mannitol (甘露醇) Multi-functional: polyester polyol (聚酯多元醇), polyether polyol (聚醚多元醇),

34

35 Polyurethane foam hard foam soft foam

36 Polymerization methods of PU
不同类型聚氨酯的聚合方法 合成弹性体时先制备低分子量二元醇，再与过量芳族异氰酸酯反应，生成异氰 酸酯为端基的预聚物，再同丁二醇扩链，得到热塑弹性体； 若用芳族二胺扩链并进一步交联，得到浇铸型弹性体； 预聚物用肼或二元胺扩链，得到弹性纤维； 异氰酸酯过量较多的预聚体与催化剂、发泡剂混合，可得到硬质泡沫塑料； 如将单体、聚醚、水、催化剂等混合，一步反应即可得到软质泡沫塑料； 单体与多元醇在溶液中反应，可得到涂料； 胶粘剂则以多异氰酸酯单体和低分子量聚酯或聚醚在使用时混合并进行反应。

37 Application of PU 聚氨酯弹性体用作滚筒、传送带、软管、汽车零件、鞋底、合成皮革、电线电 缆和医用人工脏器等；
软质泡沫体用于车辆、居室 、服装的衬垫 ，硬质泡沫体用作隔热 、吸音、包 装、绝缘以及低发泡合成木材，涂料用于高级车辆、家具、木和金属防护，水 池水坝和建筑防渗漏材料，以及织物涂层等。 胶粘剂对金属、玻璃、陶瓷、皮革、纤维等都有良好的粘着力。此外聚氨酯还 可制成乳液、磁性材料等。