聚氨酯改性聚异氰脲酸酯弹性体的合成和热性能分析

本文介绍用２，４，６－三（二甲胺基甲基）苯酚（ＤＭＰ－３０）作催化剂，采用一步法工艺制备聚氨酯改性聚异氰脲酸酯弹性体的研究工作，并用红外光谱、差热分析、热失重等方法对所制弹性体进行了定性、定量热性能分析。结果表明，通过调节催化剂用量、两组分摩尔比等工艺条件，可以使整个反应过程在１分钟之内完成，适合ＲＩＭ加工工艺；由红外光谱法和差热分析可定性确知所制材料中含有聚异氰脲酸酯三聚体和氨酯，由热失重分析可     

异氰脲酸酯改性聚氨酯弹性体的合成及研究

本文通过对异氰脲酸酯改性聚氨酯聚合反应过程的研究为基础，从各种异氰酸酯、聚醚二元醇、扩链剂及合适催化剂为反应组份，利用ＲＩＭ一步法和预聚物浇注二步法合成了系列异氰脲酸酯改性聚氨酯弹性体。通过对所制弹性体性能研究表明：在聚氨酯分子链中引入异氰脲酸酯环改性，可提高和改善弹性体的性能，随异氰脲酸酯含量的增加，弹性体的热稳定性和刚性显著增加。比较研究了两种不同方法合成的弹性体的结构形态和性能，结果表明一步法体系，由于其聚合速率快，体系中氨酯硬段和异氰脲酸酯硬段不同于二步法的较慢反应，它们没有足够时间发生相分离而互相混合，表现在ＤＳＣ曲线上只有一个Ｔｇｈ（硬段玻璃化温度），弹性体结构中含有氨酯、异氰脲酸酯相互混合的一个硬段区，结果表现在弹性体性能上，逊于结构中含有氨酯、异氰脲酸酯两个相分离的硬段区（有两个Ｔｇｈ）的二步法合成的弹性体材料。     

异氰脲酸酯改性MDI及聚氨酯弹性体合成研究

在催化剂作用下，ＭＤＩ自聚生成环状异氰脲酸酯，用此改性ＭＤＩ合成了聚氨酯弹性体。试验结果表明，ＭＤＩ在ＤＭＰ－３０催化作用下的自聚产物主要为三聚体异氰脲酸酯，ＤＭＰ－３０浓度为０．８％时，改性ＭＤＩ－的ＮＣＯ基含量约为ＭＤＩ中含量的５０％；温度对改性程度的影响不明显，在５０℃时改性程度最高；以改性ＭＤＩ合成的弹性体，其热稳定性和力学性能随改性程度的增加而提高。     

结构反应注射成型(SRIM)—─PU-PI增强塑料的研制及性能研究

在研究结构反应注射成型（ＳＲＩＭ）化学体系的基础上，以玻璃纤维毡片为增强剂，预先配制在模具中，然后进行反应注射成型的新技术－ＳＲＩＭ技术，研究制备了氨酯改性聚异氰脲酸酯（ＰＵ－ＰＩ）增强塑料（ＳＲＩＭＰＵ－ＰＩ）。     

耐热聚氨酯弹性涂料的制备

简介了用聚所酯弹性体与耐高温材料混合及对聚氨酯预聚体或原料先进行改性以及制备耐热聚氨酯弹性涂料的方法。对影响异氰脲酸酯－恶唑烷酮恶唑烷酮环和异氰脲酸酯环的因素进行了讨论。     

耐热型聚氨酯弹性体的合成

催化合成了甲苯二异氰酸酯的部分三聚体异氰脲酸酯,然后与聚醚二元醇反应,用二步法手工浇注成异氰脲酸酯改性的聚氨酯弹性体。用红外光谱法证实了产物中异氰脲酸酯的存在。根据用二正丁胺法测得的NCO基团的质量分数可计算出异氰脲酸酯的质量分数,用热重法分析了产物的热稳定性。结果表明,与普通聚氨酸弹性体相比,合成的改型聚氨酯弹性体的热稳定性得到了明显提高。     

聚异氰脲酸酯硬质泡沫塑料

本文着重研究了聚氨酯改性聚异氰脲酸酯硬质泡沫塑料制备用的催化剂活性以及泡沫制品的耐温、耐燃、耐烧蚀等性能与引入化学结构中的聚氨酯链段的影响关系。试验得出:OH/NCO当量比在0.1～0.2范围内,聚异氰脲酸酯泡沫塑料的性能优越,耐温级别高,可做高温绝热结构材料。     

一种耐热型聚氨酯弹性体的合成

在三聚催化剂的作用下,合成出了异佛尔酮二异氰酸酯的三聚体异氰脲酸酯,然后使它与聚酯多元醇反应,采用两步法手工浇注合成含异氰脲酸酯环的聚氨酯弹性体。采用红外光谱对该三聚产物进行了表征,并证实了异氰脲酸酯的存在。采用六氢吡啶法测出了异氰脲酸酯的质量分数。分别采用热重法和机械性能测试分析了弹性体的热稳定性和机械性能。结果显示,与普通聚氨酯弹性体相比,用异氰酸酯改性后的聚氨酯弹性体的热稳定性明显得到了提高。     

异氰脲酸酯改性TDI及其在聚氨酯弹性体中的应用

在催化剂存在下,使TDI受热自聚生成环状的异氰脲酸酯,用此改性TDI制得的聚氨酯弹性体具有更高的热稳定性和更好的力学性能。试验表明,在所选试验条件下,TDI受热自聚产物主要为三聚体异氰脲酸酯;DMP和乙酸钾均有明显的催化作用;DMP浓度为1%时,改性产物的NCO基含量约为TDI中含量的50%;温度对改性程度的影响不明显,以50℃左右改性程度最高;改性后的TDI在聚氨酯弹性体中的含量越高,其热性能和力学性能也越好。     

含异氰脲酸酯基团浇注型聚氨酯弹性体的动态性能研究

在催化剂作用下,合成了TDI-100型异氰脲酸酯,并与己二酸乙二醇丙二醇酯二醇（PE—PA）合成了浇注型聚氨酯弹性体,通过动态力学性能测试表明,在TDI型聚氨酯弹性体中引入异氰脲酸酯基团后,在动态条件下,弹性体的动态性能有一定程度的下降。     

Morphology of polyurethane–isocyanurate elastomers

The dynamic viscoelastic properties and thermal transition behavior of reaction injection molding (RIM) and cast polyurethane—isocyanurate elastomers have been studied as a function of various segments (soft and hard urethane, and hard isocyanurate) content. RIM and cast elastomers were prepared at different concentrations of soft and hard urethane, and hard isocyanurate segments. RIM elastomers with the higher isocyanate index (lower hard urethane and greater isocyanurate segment content) displayed an unchanged T_g (glass transition temperature of soft segment) and increasing T_gh (glass transition temperature of hard segment) related to the hard urethane and isocyanurate segments. This is due to the phase separation between the soft and the hard segments. Cast elastomers synthesized from the higher amount of 1,4-butanediol (greater hard urethane and less hard isocyanurate segment content) showed an increasing T_gs, decreasing T_gh of hard urethane segments, and an unchanged T_gh of isocyanurate segments. This is related to the phase mixing between the soft and the hard urethane segments and the phase separation of hard isocyanurate and hard urethane segments.     

耐候RIM聚氨酯弹性体的合成及性能研究

以间－四甲基亚苯基二亚甲基二异氰酸酯为Ａ组分，以聚醚二元醇，１，４－丁二醇等为Ｂ组分，利用反应注射成型法合成了ＲＩＭ－ＰＵ弹性体。通过实验确定了其最佳配方组成，并对材料性能进行了研究。结果表明，以ｍ－ＴＭＸＤＩ所制ＲＩＭ－ＰＵ弹性体不仅具有良好的机械性能，而且还具有优异的耐候性能。     

异氰脲酸酯基团对聚氨酯弹性体性能影响研究

引入异氰脲酸酯基团可提高聚氨酯弹性体的耐热性能,但同时对其他性能有一定影响。通过改变NCO含量考察异氰脲酸酯基团对聚氨酯弹性体的力学性能及耐溶剂性能的影响。力学性能测试结果表明,其硬度、拉伸强度和撕裂强度均在NCO质量分数为8％时达到极大值,分别为邵A60、10．33MPa和48．84kN／m,扯断伸长率随NCO含量增加单调减小,100％定伸强度单侧增大;耐溶剂实验表明,聚氨酯弹性体在NCO质最分数为8％时耐溶剂性能最好。     

High strength continuous glass strand—polyurethane composites by the reaction injection molding process

Considerable work has been published on the subject of filling reaction injection molded (RIM) polyurethane elastomers with discontinuous particulate fillers such as milled glass fibers, flake glass and wollastonite, RIM polyurethane elastomers are filled for three reasons: (1) to increase stiffness, (2) to decrease the linear coefficient of thermal expansion, and (3) to improve thermal dimensional stability. Discontinuous particulate fillers either do not appreciably change strength properties, e.g., tensile strength or they cause dramatic reduction in strength properties, e.g., impact resistance. To overcome these deficiencies, new fillers are necessary. Once such material is continuous glass strand mat. In order to make continuous glass strand-polyurethane composites by the RIM process, a particular balance of ingredients to produce the RIM polyurethane must be used. We will discuss the properties of these composites and suggest possible applications and future directions in which this research might proceed.     

Reaction injection molding (RIM) elastomers having superior high temperature performance

Reaction injection molding (RIM) elastomers are being seriously considered by major automotive companies as a substitute for metal in exterior body panels. One major consideration in this application is dimensional stability at a 325°F paint bake cycle. Reported here are formulations which via novel processing result in finished parts with excellent dimensional stability at 325°F. In addition, other properties such as impact resistance and flex modulus ratio improve parallel with high temperature performance. Mechanical properties as a function of processing and molding parameters are presented. Other studies are presented and a tentative explanation of the superior performance of these RIM elastomers is made.     

Reactive processing of acrylic–polyurea interpenetrating networks: reaction kinetic studies

Interpenetrating networks (IPNs), comprising a crosslinked acrylic polymer as one component and either a polyurea, a segmented copolyurea or a copoly(urea–isocyanurate) as the other component, have been formed by reaction injection moulding (RIM). The effects on the processability and the formation of the IPNs of (i) the crosslinker concentration in the acrylic component, (ii) the functionality of the amine‐functionalized polyether used for the polyurea, and (iii) the weight fractions of acrylic components are evaluated. Reaction kinetics during RIM processing of the IPNs are studied using adiabatic temperature rise (ATR) measurements. The macroscopic structures of RIM materials, determined via optical microscopy, are used to assess the mixing characteristics operative during reactive processing of the various IPNs. The results are interpreted in terms of differences in the rates of polymerization and in the solubilities of the acrylic‐ and polyurea‐forming components. © 2001 Society of Chemical Industry