聚硅氧烷聚脲嵌段共聚物的TEM及SAXS研究

采用透射电子显微镜与小角X光散射分别研究了不同软、硬段分子量及软段极性对聚硅氧烷聚脲多嵌段共聚体系微相结构的影响。结果表明,增加软段分子量及硬段含量有利于聚硅氧烷与聚脲的相分离。将极性氰丙基引入聚硅氧烷后两相混合度明显改善,同时聚脲硬段粒径减小并趋于均一。在聚氰丙基甲基硅氧烷基体中增加聚脲含量及其分子量,则两相界面厚度也随之增大。     

聚氰丙基甲基硅氧烷-聚脲嵌段共聚物的结构和性能

本文以氨丙基封端聚(氰丙基,甲基)硅氧烷(CH_2)_3CN:CH_3=1:5),MDI和EDA为原料,采用DMAC单一溶剂合成了一系列高软段分子量(Mn=3000～9000)和高硬段含量(7～30%wt)的多嵌段共聚物。产物为透明热塑性弹性体,具有良好的成膜性能和宽阔的使用温区,其杨氏模量比相应的聚二甲基硅氧烷-聚脲显著提高。通过FT-IR,WAXD,DSC,DMA等证明其硬段为近程有序结构,氰丙基与聚脲硬段有氢键作用,这一作用力使两相相溶性提高,“界面厚度”增加。氰丙基的引入和硬段含量的增加对材料相结构和力学性能有显著影响。     

含呱嗪聚硅氧烷聚脲聚氨酸及其离聚物的研究

以氨丙基封端聚二甲基硅氧烷及脲键改性聚硅氧烷低聚体分别与4，4－二异氰酸酯二苯甲烷（MDI)反应，并用1，4二（2－羟乙基）－呱嗪（N）扩链，合成了一系列含氮杂环聚氨酯共聚物。产物为透明热塑性弹性体，具有良好的成膜性能和宽阔的使用温区，通过碘乙烷和γ－丙磺酸内酯对上述样品进行季铵化，合成了阳离子型及双离子型离聚物。用傅里叶红外光谱（FT－IR）、示差量热分析（DSC）、动态力学谱（DMTA）、力学性能等方面对样品进行了表征。结果表明，在聚硅氧烷中引入脲键，提高了软、硬段两相的相容性。体系中既有软段间的氢键作用又有两相间的氢键作用，从而使这类材料的杨氏模量、抗张强度和断裂伸长均明显高于相应的聚二甲基硅氧烷聚脲聚氨酯体系。     

多嵌段聚硅氧烷聚脲共聚物及双离子型聚硅氨酯的表面性质的研究

本文利用光电子能谱(ESCA)和表面接触角研究了多嵌段聚硅氧烷聚脲共聚物(PUSE)和双离子型聚硅氨酯(PUSM)的表面性质,发现PUSE和PUSM中的软段聚硅氧烷均在表面富集;提高本体的相分离程度,更有利于软段的表面富集;但在50层内,硬段仍有一定的比例,表面层仍是多相结构。在PUSE中,接触角和凝血时间随聚硅氧烷软段比例增加而增加,在PUSM中,随离子化程度的提高,亲水性提高,接触角变小,凝血时间缩短。     

含呱嗪聚硅氧烷聚脲聚氨酯及其离聚物的研究

以氨丙基封端聚二甲基硅氧烷及脲键改性聚硅氧烷低聚体分别与４，４－二异氰酸酯二苯甲烷（ＭＤＩ）反应，并用１，４二（２－羟乙基）一呱唪（Ｎ）扩链，合成了一系列含氮杂环聚氨酯共聚物，产物为透明热塑性弹性体，具有良好的成膜性能和宽阔的使用温区。通过碘乙烷和ｖ－丙磺酸内酯对上述样品进行季铵化，合成了阳离子型及双离子型离聚物。用傅里叶红外光谱（ＦＴ－ＩＲ）、示差量热分析（ＤＳＣ）、动态力学谱（ＤＭＴＡ）、力学性能等方法对样品进行了表征，结果表明，在聚硅氧烷中引人脲键，提高了软、硬段两相的相容性，体系中既有软段间的氢键作用又有两相间的氢键作用，从而使这类材料的杨氏模量、抗张强度和断裂伸长均明显高于相应的聚二甲基硅氧烷聚脲聚氨醋体系。     

聚醚型多嵌段共聚物软链段结晶特性的研究

本文使用虹外光谱及膨胀计等方法,对聚四亚甲基醚二醇类多嵌段共聚物的软链段结晶性进行了研究。在聚醚-聚酯多嵌段共聚物中(PTMEG>60％),其软链段结晶的熔点和结晶速率均随PTMEG含量减少而下降。而在聚醚-聚脲胺酯多嵌段共聚物中,由于N—H和C—O—C之间氢键的作用,即使在低温下,其软链段也难于结晶。此外,高倍拉伸会提高上述二类多嵌段共聚物中软链段结晶的熔点和结晶速率。     

含有机硅三元多嵌段共聚物的研究

以双酚Ａ聚砜（ＰＳＦ）为硬段、聚对羟基苯乙烯（ＰＨＳ）为半硬段、聚二甲基硅氧烷（ＰＤＭＳ）为软段合成了三元多嵌段共聚物，并对其动态力学和抗张性能比较研究，结果表明该三元多嵌段共聚物为多相结构；在引入半硬段ＰＨＳ后两相间的界面相增宽，粘接力增大，其强度和模量高且稳定，使含有机硅高分子材料强度低的弱点得以改善，扭（ＴＢＡ）结果显示，这种三元多嵌段共聚物具有多重转变，且在－２０℃至５０℃间有两个较大的几     

1,5-萘二异氰酸酯与1,4-丁二醇基为基质的多嵌段聚氨酯弹性体的合成与性能

利用 1 ,5_萘二异氰酸酯 (NDI)和 1 ,4_丁二醇 (BDO)为均匀硬质分子单体 ,与不同软质分子单体 (聚醚、聚酯、聚硅氧烷 )缩合制备多嵌段聚氨酯弹性体 ,详细研究了硬嵌段相 (NDI)弹性体的结构与性能间的关系 ,发现随着硬嵌段相长度的增加 ,或者氨基甲酸酯中胺基与聚醚、聚酯、聚硅氧烷中软段氧原子间氢键的减弱 ,都导致微相分离程度的增加 ,造成聚合物熔点和熔化热的升高。硬嵌段相熔化的多峰行为是由于形成了NDI/BDO半微晶区 ,在退火时转变为更加有序的结晶微区 ,当温度高于 1 80℃时 ,由于氢键的断裂 ,NDI/BDO硬嵌段发生分解反应 ,该过程源于不很有序的硬嵌段半结晶微区。当温度高于 2 5 0℃时 ,发生快速的分解。在动态力学行为方面 ,NDI基聚醚弹性体比其它硅氧烷基的弹性体展示了更高的硬嵌段区的稳定性 ,同时 ,在使用温度范围内 ,也显示出最高的储能模量值 ,表明刚性对温度的依赖性 ,以及NDI/BDO硬嵌段中活性填料的显著影响     

不同硬段含量脂肪族聚脲的结构与性能研究

通过端氨基聚醚、异佛尔酮二异氰酸酯和异佛尔酮二胺反应 ,合成了一系列不同硬段含量的脂肪族聚脲 ,并用DSC和FTIR等考察了硬段含量对聚脲的微观结构与力学性能的影响 .研究结果表明 ,聚脲呈现部分微观分相的形态 ,随硬段含量增加 ,聚脲中软段和硬段间的相容性提高 ,脲羰基的氢键化程度增加 ,但软段的玻璃化转变温度变化不大 ;此外 ,材料的拉伸强度、撕裂强度和硬度等也随着硬段含量的增加而显著提高 .     

含有机硅三元多嵌段共聚物的研究──Ⅱ．（PSF－PDMS－PHS）_n的动态力学性能研究

以双酚Ａ聚砜（ＰＳＦ）为硬段、聚对羟基苯乙烯（ＰＨＳ）为半硬段、聚二甲基硅氧烷（ＰＤＭＳ）为软段合成了三元多嵌段共聚物，并对其动态力学性能和抗张性能进行了比较详细的研究，结果表明该三元多嵌段共聚物为多相结构；在引入半硬段ＰＨＳ后两相间的界面相增宽，粘接力增大，其强度和模量高且稳定，使含有机硅高分子材料强度低的弱点得以改善。扭辩分析（ＴＢＡ）结果显示，这种三元多嵌段共聚物具有多重转变，且在－２０℃至５０℃间有两个较大的几乎重叠的吸收峰；这表明这种三元多嵌段共聚物的相分离结构较为复杂，并有良好的阻尼性能。     

Synthesis and characterization of polydimethylsiloxane polyurea-urethanes and related zwitterionomers

A series of segmented polyurea urethane and polyurea block copolymers based on a hexane diisocyanate (HDI) modified aminopropyl terminated polydimethylsiloxane soft segment was synthesized. The hard segments consisted of 4,4′-methylene diphenylene diisocyanate (MDI) which was chain extended with 1,4-butanediol (BD), N-methyldiethanolamine (MDEA), or ethylene diamine. Zwitterionomers were prepared by quaternizing the tertiary amine of the MDEA extended material with γ-propane sultone. The effect of chemical structure on the extent of phase separation and physical properties was studied using a variety of techniques including thermal analysis, dynamic mechanical spectroscopy, tensile testing, and small-angle x-ray scattering. It was observed that the compatibility between the nonpolar polydimethylsiloxane soft segments and the polar urethane hard segments was improved by inserting HDI linkages into the polydimethylsiloxane soft segments. The aggregation of hard segments was enhanced by increasing hard-segment content or by the introduction of ionic functionality. The tensile strength and modulus of these materials was higher than those of polyurethanes containing soft segments based on polydimethylsiloxane and its derivatives.     

Novel synthesis of polyimide–polyhybridsiloxane block copolymers via polyhydrosilylation: Characterization and physical properties

The insertion of soft polysiloxane segments into a polyimide backbone introduces changes in its properties (processability, low surface tension, gas permeability, and lower dielectric constant). Generally, these polyimide–polysiloxane copolymers are synthesized by the condensation of a dianhydride with an aromatic diamine and an amine telechelic polysiloxane, or by transimidization between an aminopyridine‐terminated oligoimide and an amine end‐capped oligosiloxane. This study investigated another route to obtain perfectly alternating polyimide–polyhybridsiloxane (PI–PHSX) block copolymers. The hydrosilylation, widely studied previously, was performed to elaborate copolymers from an allyl telechelic polyimide and a hydrosilane telechelic polyhybridsiloxane. The use of a telechelic polyhybridsiloxane as a soft segment brought better thermostability and better chemical resistance in comparison with an oligosiloxane based on ? Si(CH₃)₂? O? units. Using the same allyl telechelic polyimide moiety but varying the size of the hybrid siloxane part, we obtained different PI–PHSX block copolymers, leading to thermoplastic elastomers (TPE). We investigated the effect of the soft‐segment length on the thermal resistance, activation energy of thermal degradation, mechanical behavior, and surface properties of a series three PI–PHSX block copolymers containing 36, 54, and 75 wt % polyimide. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2414–2425, 2001     

聚对苯二甲酸丁二酯-聚四亚甲基醚多嵌段共聚物的研究

合成了硬段含量和软段分子量不同的聚对苯二甲酸丁二酯-聚四亚甲基醚(PBT-PTMG)多嵌段共聚物。研究了硬段含量和软段分子量对嵌段共聚合过程的影响。当软段分子量较大、硬段含量较高时,在嵌段共缩聚过程中有均聚物伴生。当软段分子量在2000左右,硬段含量在20％左右时,基本上不生成均聚物。硬段重量含量为 20％的低硬段 PBT-PTMG多嵌段共聚物是结晶的。由它纺成的弹体纤维有良好的力学性能和弹性回复。热处理能改进纤维的弹性回复。     

Poly(chloropropylmethyl-dimethylsiloxane)–polyurethane elastomers: Synthesis and properties of segmented copolymers and related zwitterionomers

A series of polyurethane block copolymers based on hydroxybutyl terminated poly(chloropropylmethyl-dimethylsiloxane) and poly(tetramethylene oxide) soft segments of molecular weights 2100 and 2000, respectively, were synthesized. The hard segments consisted of 4,4′-methylenediphenylene diisocyanate (MDI) that was chain extended with either 1,4-butanediol (BD) or N-methyldiethanolamine (MDEA). The materials chain extended with MDEA were ionized using 1,3-propane sultone. The weight fraction of the hard segments was in the range 0.30–0.45. The effect of mixed soft segments, chain extenders, and zwitterionization on the extent of phase separation and physical properties was studied by utilizing differential scanning calorimetry and dynamic mechanical, stress-strain, and Fourier Transform Infrared spectroscopy experiments. All of these short segment block copolymers showed nearly complete phase separation. The zwitterionomer materials exhibited ionic aggregation within the hard domains. Although hard segment crystallinity or ionic aggregation did not affect the morphology, hard domain cohesion was important in determining the tensile and viscoelastic properties of these elastomers.     

New Fluorinated Poly(imide siloxane) Random and Block Copolymers with Variation of Siloxane Loading

Several new random and block copoly(imide siloxane)s have been prepared by the solution polycondensation of commercially available 4,4′-oxydianiline (ODA) and amino-propyl terminated polydimethylsiloxane (APPS) with 4,4′-(hexafluoro-isopropylidene)diphthalic anhydride (6FDA). The siloxane loading was kept to 10, 20, 30, 40 and 50 wt% in the copolymers. The random copolymers were prepared by a one pot solution imidization technique, and two pot solution imidization technique was adopted for the synthesis of the block copolymers. The diamine ODA and the dianhydride 6FDA composed the hard block segment, while APPS and 6FDA composed the soft block segment. The hard block length was kept constant while the soft block lengths were varied by varying the siloxane loading. Accordingly, block copoly(imide siloxane)s were prepared on increasing the soft block lengths (DP) from 3 to 6, 10, 18 and 36 for fixed hard block length of 22. The resulting polymers have been well characterized by IR, NMR and GPC techniques. Thermal and mechanical properties of the random and block copolymers were compared with the already reported homopolyimide without siloxane moiety.     

主链型液晶聚硅氧烷聚氨酯的合成及性质

合成了主链型联苯类及氧化偶氯苯类液晶聚硅氧烷聚氨酯弹性体，采用红外光谱，示差扫描量热，动态粘弹谱及带热台偏光显微镜等方法对聚合物进行了表征，讨论了它们的结构与性能．研究结果表明，这一系列多嵌段聚氨酯多数是向列型的液晶高分子聚合物，液晶相的形成同嵌段聚氨酯样品的软硬段相互作用有着密切的联系     

Polydimethylsiloxane–polyurethane elastomers: Synthesis and properties of segmented copolymers and related zwitterionomers

A series of polyurethane block polymers based on hydroxybutyl-terminated polydimethyl-siloxane soft segments of molecular weight 2000 were synthesized. The hard segments consisted of 4,4′-methylenediphenylene diisocyanate (MDI) which was chain extended with either 1,4-butanediol (BD) or N-methyldiethanolamine (MDEA). The MDEA-extended materials were ionized by using 1,3-propane sultone. The weight fraction of hard segments was in the range 0.13–0.39. The morphology and properties of these polyurethane elastomers were studied by a variety of techniques. All of these short-segment block copolymers showed nearly complete phase separation. The zwitterionomer materials exhibited ionic aggregation within the hard domains. Hard-segment crystallinity or ionic aggregation did not affect the morphology. Hard-domain cohesion was found to be a more important factor than hard-domain volume fraction in determining the tensile and viscoelastic properties of these elastomers.     

On the photoreactivity of diacetylene containing thermoplastic block copolymers

A group of block copolymers containing diacetylenes as chain extenders in their hard segments was prepared, based on urethanes, esters, ureas, and amides as hard segments and polybutadienes, polyethers, polyesters, and polysiloxanes as soft segments. Almost all block copolymers were photoreactive, but there was a wide range of sensitivities. The photoreactivity of the copolymers was found to depend on the reactivity of the monomer unit, on the width of the diacetylene stacks in the hard segments, and on the degree of phase separation in the solid films. To explore the range of monomer reactivities we prepared 15 crystalline monomers. Urethanes were in general the most reactive, and this was attributed in part to the specific effect of hydrogen bonding which brings about a shortening of the C₁ to C₄ distance between diacetylenes tend to reduce the photoreactivity. The behavior of identical diacetylene units in the monomer crystal, in the homopolymer, and in the block copolymer is discussed in this paper.