扩链剂对TODI型聚氨酯弹性体性能的影响研究

以3,3′-二甲基-4,4′-联苯二异氰酸酯(TODI)和聚四氢呋喃均聚醚(PTMG)合成聚氨酯预聚体,分别以1,4-丁二醇(BDO)和二胺类的3,5-二甲硫基甲苯二胺(E-300)、3,3′-二氯4,4′-二氨基二苯甲烷(MOCA)和4,4′-亚甲基双(3-氯-2,6-二乙基苯胺)(M-CDEA)为扩链剂,研究了扩链剂对聚氨酯弹性体力学性能和耐热性能的影响。结果表明:以M-CDEA为扩链剂的TODI弹性体综合力学性能最为优异;在耐热性能方面,以4种扩链剂制备的TODI型聚氨酯弹性体的顺序为MCDEA>MOCA>BDO>E-300。     

M-CDEA在聚氨酯弹性体中的应用研究

分别以聚ε-己内酯多元醇(PCL)、聚四氢呋喃醚二元醇(55PTMG)和甲苯二异氰酸酯(TDI)为原料合成聚氨酯预聚体,分别用M-CDEA[4,4′-亚甲基-双-(3-氯-2,6-二乙二基苯胺)]和3,3’-二氯-4,4’-二氨基二苯基甲烷(MOCA)作为扩链剂合成聚氨酯弹性体,比较了两种不同扩链剂对聚氨酯弹性体的力学性能和耐热性能的影响。实验结果表明:与MOCA相比,由M-CDEA扩链的聚氨酯弹性体的硬度、撕裂强度、回弹和耐磨性较高。DSC和TG测试结果表明:经M-CDEA扩链的聚氨酯弹性体的耐热性能优于MOCA。     

含砜基扩链剂对聚氨酯微相分离和性能的影响

以4,4'-二羟基二苯砜为原料合成了二[4-(4-氨基苯氧基)苯基]砜(BAPS),采用红外光谱(FTIR)、元素分析(EA)和核磁共振氢谱(1H-NMR)等对其结构进行了表征;并以BAPS为扩链剂制备了含砜基聚氨酯弹性体,采用原子力显微镜(AFM)、FTIR、热失重(TG)、广角X-射线衍射(WAXD)和力学性能测试等手段研究了此弹性体的微相分离结构和性能.结果表明,所得产物BAPS的结构与预期设计相符;以BAPS为扩链剂合成的含砜基聚氨酯弹性体微相分离明显,具有较好的耐热性和机械性能.     

高性能聚氨酯密封材料的微相结构和热性能(Ⅱ)

采用聚碳酸酯二醇(PCDL)、聚四亚甲基醚二醇(PTMG)和4,4′-二苯基甲烷二异氰酸酯通过预聚体法和半预聚体法合成了一系列聚氨酯(PU)弹性体。采用示差热扫描量热,热失重和动态力学性能分析对PU弹性体的性能及多元醇结构和组成,合成方法对PU弹性体微相结构形态的影响进行了研究。结果表明,由预聚体法合成的弹性体的微相分离程度高于半预聚体法,二胺扩链的弹性体的硬段结晶性优于二醇扩链的弹性体,单一二醇合成弹性体的硬段的结晶性优于混合二醇合成的弹性体,几种弹性体的的硬段结晶性依次为PU-LF-950APU-PCDL≈PUPTMGPU-PCDL+PTMG。几种弹性体的热稳定性依次为PU-PCDLPU-PCDL+PTMG≈PU-PTMGPU-LF-950A。PU-LF-950A和PU-PTMG的低温性能优于PU-PCDL和PU-PCDL+PTMG。PU-LF-950A还具有较好的高温动态性能和微相分离程度。     

聚氨酯脲微相分离程度及性能研究

以端羟基聚丁二烯丙烯腈(HTBN)和聚醚多元醇(N210)为软段,以甲苯二异氰酸酯(TDI)和异佛尔酮二异氰酸酯(IPDI)以及4,4′-二氨基-3,3′-二氯二苯甲烷(MOCA)和二甲硫基二胺基甲苯(DMTDA)为硬段,制备了一系列聚氨酯脲(PUU)弹性体。采用傅里叶变换红外光谱分析(FT-IR)、热重分析(TGA)、动态黏弹(DMA)、材料拉伸测试机等测试手段对合成的PUU进行了结构与性能表征,研究了聚氨酯体系中各组分对弹性体微相分离程度及各种性能的影响。结果表明,对称性较高且分子结构中含有刚性苯环的扩链剂和异氰酸酯有利于微相分离程度的提高。     

扩链剂对IPDI基透明聚氨酯弹性体的影响

采用异佛尔酮二异氰酸酯(IPDI)和不同结构的扩链剂、多元醇合成了透明聚氨酯弹性体，通过DSC、TG、WAXD等研究了聚氨酯弹性体的形态结构和力学性能、热稳定性及光学透明性。结果表明，扩链剂结构对聚氨酯弹性体形态结构和力学性能、热稳定性及光学透明性有很大影响。降低扩链剂长度有利于微晶的长大、微相分离程度及力学性能的提高；增加扩链剂用量，聚氨酯弹性体的微相分离程度、微晶尺寸、力学性能及热稳定性能提高；硬段含量对聚氨酯弹性体光学透明性的影响不明显。     

室温固化型MDI体系聚氨酯弹性体力学性能的研究

以不同结构多元醇和4,4′-二苯基甲烷二异氰酸酯(MDI-100)合成预聚体,再与不同扩链剂反应制备室温固化MDI型聚氨酯弹性体。讨论了多元醇种类、扩链剂种类、扩链系数、稀释剂用量、催化剂种类对聚氨酯弹性体力学性能的影响。结果表明,结构规整的多元醇制备的聚氨酯弹性体综合性能较好;二醇类扩链剂1,4-丁二醇(1,4-BDO)和对苯二酚二羟基乙基醚(HQEE)制备的弹性体性能较好,操作工艺可行;扩链系数以0.85~1.0为宜;适宜稀释剂质量分数为5%~10%;MDI室温固化体系的催化剂可选用HDcat。     

苯胺三聚体/1,4-丁二醇为混合扩链剂的聚氨酯弹性体的合成与表征

在酸性介质中,采用化学氧化的方法,利用苯胺为原料,对苯二胺为封端剂,制得双氨基封端的苯胺三聚体(TA)和四聚体(BA),并利用索氏抽提技术,将二者成功分离。以聚四氢呋喃二醇(PTMEG)和2,4-二苯基甲烷二异氰酸酯与4,4′-二苯基甲烷二异氰酸酯混合物(MDI-50)合成聚氨酯预聚体,通过双氨基封端的TA与1,4-丁二醇(BDO)为混合扩链剂,得到聚氨酯弹性体(PUE)。并利用拉伸实验、傅立叶红处光谱分析、热重(TGA)分析、动态力学(DMA)分析等测试方法对合成的聚氨酯弹性体的结构、力学性能和热学性能等进行了表征。     

二醇扩链剂对聚醚聚氨酯弹性体性能的影响

研究了以乙二醇、一缩二乙二醇、1,4-丁二醇和1,6-己二醇作为扩链剂对聚醚聚氨酯弹性体性能的影响。结果表明,扩链剂链长越短,弹性体的微相分离程度和力学性能越好;以BDO扩链为例,随其用量的增加,弹性体的性能提高,达到一定值后再增加用量性能反而下降;混合扩链剂有助于聚氨酯弹性体综合性能的提高。     

PCL/MDI体系聚氨酯弹性体力学性能的研究

以聚己内酯二醇(PCL)和4,4′-二苯基甲烷二异氰酸酯(MDI)为原料,用二元醇1,4-丁二醇(BDO)和三元醇(TMP)混合物作扩链剂制备了聚氨酯(PU)弹性体,研究了预聚体NCO基含量、扩链剂用量和扩链系数对聚氨酯弹性体力学性能的影响。结果表明,聚氨酯弹性体的硬度、模量和强度随预聚体NCO基含量的增加而增加,扩链剂三元醇质量分数超过20%后,弹性体力学性能下降幅度较大,扩链系数大于0.95时,聚氨酯的力学性能急剧降低。     

Thermal and dynamic mechanical characterization of polyurethane–urea–imide coatings

A series of NCO terminated polyurethane (PU)–imide copolymers were synthesized by a systematic three‐step process and were chain extended with different diol/diamine chain extenders. In the first step, isocyanate terminated PU prepolymers were prepared by reacting soft segments such as polyester (PE) polyols and polyether polyols such as polypropylene glycol (PPG‐1000) with hard segments like 2,4‐tolylene‐diisocyanate (TDI) or isophorone‐diisocyanate (IPDI) with NCO/OH ratio 2:1. In the second step, thermally stable heterocyclic imide ring was incorporated using isocyanate terminated PU prepolymers by reacting with pyromellitic dianhydride (PMDA) in a excess‐NCO:anhydride ratio of 1:0.5. The surplus NCO content after imidization was both moisture cured or partially reacted with chain extender and moisture cured. The films were characterized by thermogravimetric (TG), differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) instruments. The adhesion strength of these coatings on mild steel (MS), copper (Cu), and aluminum (Al) is dependent on the nature of the substrate. The TGA analysis show good thermal stability. The DMTA results show the microphase separation between the different hard and soft segments. Finally, a structure to property correlation was drawn based on the structure of the soft, hard, and chain extender and the observed properties are useful for understanding and design of intelligent coatings. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3158–3167, 2006     

FT-IR and XPS studies of polyurethane-urea-imide coatings

A series of polyurethane (PU)-urea-imide coatings were synthesized by a systematic three-step reaction process. Initially isocyanate terminated PU prepolymers were prepared by reacting soft segments such as polyester polyols (prepared from neopentyl glycol, adipic acid, isophathalic acid and trimethylol propane) or polyether polyols (polypropylene glycol-1000) with hard segments such as 2,4-toluene diisocyanate or isophorone diisocyanate with NCO/OH ratio of 2:1. Heterocyclic imide ring into the PU backbone was incorporated by co-polymerization with pyromellitic dianhydride (PMDA) from the excess NCO groups in the PU prepolymer with an NCO/anhydride ratio of 1:0.5 and the surplus NCO content after imidization was moisture cured. PU-urea-imide coatings were also obtained by partial chain extension of the excess NCO groups in the NCO terminated PU-imide copolymers, and the remaining excess NCO groups were completely reacted with atmospheric moisture. The obtained polymers were analyzed with Fourier transform-infrared (FT-IR) and angle resolved X-ray photoelectron spectroscopy (AR-XPS). The type and change in intermolecular H-bonding interaction in the PU-urea-imide films with structural variables was identified by deconvolution of the FT-IR spectra using Origin 6.0 software through Gaussian curve-fitting method. The FT-IR analyses of the PU-urea-imide coating films show dependence of phase separation on the nature of chain extender. Surface characterization data from AR-XPS suggests the dependence of phase segregation behaviour on the nature of the chain extender, which also supports the FT-IR observations.     

Synthesis and characterization of new functional poly(urethane‐imide) crosslinked networks

To synthesize new functional poly(urethane‐imide) crosslinked networks, soluble polyimide from 2,2′‐bis(3,4‐dicarboxyphenyl) hexafluoropropane dianhydride, 4,4′‐oxydianiline, and maleic anhydride and polyurethane prepolymer from polycaprolactone diol, tolylene 2,4‐diisocyanate and hydroxyl ethyl acrylate were prepared. Poly(urethane‐imide) thin films were finally prepared by the reaction between maleimide end‐capped soluble polyimide (PI) and acrylate end‐capped polyurethane (PU). The effect of polyurethane content on dielectric constant, residual stress, morphology, thermal property, and mechanical property was studied by FTIR, prism coupler, Thin Film Stress Analyzer (TFSA), XRD, TGA, DMTA, and Nano‐indentation. Dielectric constant of poly(urethane‐imide) thin films (2.39–2.45) was lower than that of pure polyimide (2.46). Especially, poly(urethane‐imide) thin films with 50% of PU showed lower dielectric constant than other poly(urethane‐imide) thin films did. Lower residual stress and slope in cooling curve were achieved in higher PU content. Compared to typical polyurethane, poly(urethane‐imide) thin films exhibited better thermal stability due to the presence of the imide groups. The glass transition temperature, modulus, and hardness decreased with increase in the flexible PU content even though elongation and thermal expansion coefficient increased. Finally, poly(urethane‐imide) thin films with low residual stress and dielectric constant, which are strongly affected by the morphological structure, chain mobility, and modulus, can be suggested to apply for electronic devices by variation of PU. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 113–123, 2006     

有机硅/丁二醇扩链剂混合比对混合大二醇基聚氨酯弹性体的性能影响

以α,ω-双(γ-羟丙基)聚二甲基硅氧烷(BHPDMS)和聚氧四甲基二醇(PHMO)混合大二醇为软链段;以1,4-丁二醇(BDO)为主要扩链剂,1,3-双(4-羟丁基)-1,1,3,3-四甲基二硅氧烷(BHTD)为次级扩链剂,所有试样中硬链段均由4,4'-二苯基甲烷二异氰酸酯(MDI)和混合扩链剂所构成,且w(硬链段)=40%;采用两步溶液聚合法制备混合大二醇基芳香聚氨酯(PU)弹性体。通过力学性能测试、差示扫描量热法(DSC)和动力学热分析法(DMTA),研究了混合扩链剂中n(BDO)/n(BHTD)比值对该PU弹性体性能的影响。结果表明,当n(BDO):n(BHTD)=3:2时,所得PU弹性体具有优异的综合性能;引入BHTD扩链剂后,破坏了硬链段的有序性。     

侧氨基聚硅氧烷改性聚氨酯涂层剂的制备与性能

以侧氨基聚硅氧烷(SAPDMS)、聚四氢呋喃醚、聚乙二醇为混合软段,二羟甲基丙酸为亲水扩连剂,1,4-丁二醇为硬段调节剂,与异佛尔酮二异氰酸酯反应合成了水性有机硅改性聚氨酯(WSSPU),并以WSSPU为基础制备了防水透湿织物涂层剂。分别采用红外光谱、差热扫描量热仪、动态力学分析仪、正电子湮灭寿命谱等表征了WSSPU膜的组成与微观结构,考察了WSSPU膜的力学性能和涂层织物的防水透湿性能。结果表明,当侧氨基聚硅氧烷用量(质量比)< 15%时,可以制得稳定的乳液。聚硅氧烷改性后膜内部微相分离结构更加明显,自由体积空洞变大,透湿性能提高。     

液化MDI基形状记忆聚氨酯扩链剂的选择研究

在选定液化MDI和聚己二酸丁二醇酯(PBAG)软段原料的前提下，采用双酚A(FA)、乙二醇(ED)、1，4-丁二醇(BD)、1，6-己二醇(HD)、一缩乙二醇(DE)扩链剂合成了一系列形状记忆聚氨酯(SMPU)；用FT-IR、DSC对样品的结构进行了分析，并考察了它们的形状记忆性能和力学性能。结果发现，扩链剂对SMPU有一定影响，用FA、ED扩链的SMPU具有较好的微相分离，而DE扩链的具有较好的软段结晶性能；FA、HD的SMPU具有较低的形状回复温度和较快的形状回复速率，HD、DE扩链的则具有较好形状固定性能，FA、DE扩链的SMPU循环使用性能较好；同时FA、HD的SMPU具有较高的弹性模量与力学强度。     

Characteristics of the degradation and improvement of the thermal stability of poly(siloxane urethane) copolymers

This work investigates the characteristics of the thermal degradation of poly(ether urethane) (E‐PU) and poly(siloxane urethane) (S‐PU) copolymers by thermogravimetric analysis (TGA) and thermogravimetric analysis/Fourier transform infrared spectroscopy (TG–FTIR). The stage of initial degradation for E‐PU was demonstrated as a urethane‐B segment consisting of 4,4′‐diphenylmethane diisocyanate (MDI) and 1,4‐butanediol. Moreover, the urethane‐B segment in the copolymers had the lowest temperature of degradation (ca. 200°C). The degradation of E‐PU was determined by TGA and TG–FTIR analyses and had three stages including seven steps. Although the soft segment of S‐PU possessed the thermal stability of polydimethylsiloxane (PDMS), the unstable urethane‐B segment existed in S‐PU. Therefore, the initial degradation of S‐PU appeared around 210°C. The four stages of degradation of S‐PU involved eight steps, as revealed by TG–FTIR, which identified the main decomposition products: CO₂, tetrahydrofuran, and siloxane decomposition products. The imide group with high thermal stability was to replace the urethane‐B segment of S‐PU, which had the lowest thermal stability herein. The poly(siloxane urethane imide) (I‐PU) copolymer around 285°C exhibited a high initial temperature of degradation, and the initial degradation occurred at the urethane‐S segment consisting of MDI and PDMS. The degradation of I‐PU was similar to that of S‐PU and had four stages including six steps. Moreover, the degradation region of the imide group between 468 and 625°C was merged into the degradation stage of the siloxane decomposed products. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

High performance poly(urethane-imide) prepared by introducing imide blocks into the polyurethane backbone

A series of novel linear poly(urethane-imide)s were synthesized by the reaction between isocyanate-terminated polyurethane (PU) prepolymer and amine- or anhydride-terminated oligoimide. PU prepolymer was synthesized by reacting polyethylene adipatediol of molecular weight 1000 with tolylene-2,4-diisocyanate at the molar ratio of 2:3 or 1:2. Oligoimide was synthesized from the reaction of 4,4′-(hexafluoroisopropylidene)diphthalic acid with 4,4′-oxydianiline at various molar ratios. Equimolar amounts of PU prepolymer and oligoimide were reacted in N-methyl-2-pyrrolidone, followed by casting on glass plates and heat treatment at 100 and 150 °C for 1 h each to give linear poly(urethane-imide)s as transparent yellowish brown films. Poly(urethane-imide) films with less of 30% of imide component became elastomer, and films with more than 36% imide component became plastic. The effects of end-groups of oligoimide, molecular weight of oligoimide, and molecular weight of PU prepolymer on the solvent resistance, the tensile properties, viscoelastic properties, and thermogravimetric properties of poly(urethane-imide) films were systematically examined. Solvent resistance and tensile modulus of poly(urethane-imide) films from amine-terminated oligoimides were better than those from anhydride-terminated oligoimides. On the other hand, thermal stability and elongation at break for the poly(urethane-imide) films from anhydride-terminated oligoimides were higher than those from amine-terminated oligoimides.     

Mechanical and dynamic properties of graft polyurethane/allyl novolac resin simultaneous interpenetrating network

Two series of polyurethane (PU)/allyl novolac resin simultaneous interpenetra ing networks (SINs) were synthesized. The PU components were prepared by reacting 4,4′-diphenyl methane diisocyanate with poly(tetramethylene oxide) (PTMO), whose molecular weight range was 600–700 (for convenience, this polymer was called UT1), 900–1050 (UT2) and 1900–2100 (UT3), respectively. The phenolic resin component was synthesized by substituting the hydroxy groups of the phenolic resin with the allyl group. To prove that the alkene group can be applied as a binding element between the networks to improve the network compatibility, trimethylol propane monoally ether (TMPME) with a double bond was chosen as the PU chain extender in one series of the PU/allyl novolac resin SINs (designated TUT1, TUT2 and TUT3 for different molecular weights of PTMO used as PU soft segments). After a detailed study of the thermal, mechanical, and dynamic properties and morphology, the extent of phase mixing of the graft PU/allyl novolac resin SINs (TUT series SINs) was significantly improved over that of UT series SINs. This result is consistent with the loss tangent shift in dynamic mechanical analysis measurements and with transmission electron microscope micrographs. The mechanical properties of the graft SINs (TUT series) were lower than those of the original SINs (UT series) because TMPME with bulky structure was used as the chain extender of PU.