Preparation, morphology and mechanical properties of acrylate-modified polyurethane/unsaturated polyester resin graft-IPNs

Acrylate modified polyurethane resin was first synthesized, and interpenetrated with unsaturated polyester resin to form IPNs and gradient IPNs which cured at room temperature. The polymerization process was traced by an IR spectroscopy technique and the simultaneous interpenetrating techniques were determined. The morphology of these IPNs were estimated by TMA and TEM methods. The results indicated that large amount of interpenetrating and entanglement make T g linked up effectively, and domains between two phases can be in nanometre ranges, which changed with composition ratios. The mechanical properties results showed that IPNs varied from elastomeric to plastic materials. It was noteworthy that, with the introduction of modified groups and the formation of graft construction in IPNs, the miscibility in the systems was improved a lot. These further led to the improved mechanical properties of IPNs with elastomer reinforced and plasticizer toughened as well. The reinforced miscibility between the networks can apparently change mechanical property especially for the gradient ones when the materials are elongated.

STUDY ON HYDROLYSIS RESISTANT POLYCARBONATE POLYURETHANE EPOXY RESIN BLENDS

This paper studies the structure and properties of the polycarbonate polyurethane epoxy resin (PCPU EP) blends being resistant to hydrolysis.The samples were analyzed by an infrared spectrometer,a differential scanning calorimeter,a scanning electron microscope and a dynamic viscoelastometer.The results show that PCPU EP blends have excellent resistance to hydrolysis and mechanical properties at the ratio of PCPU to EP equal to 10/100 (wt/wt).

Curing mechanism of TDE-85/MeTHPA epoxy resin modified by polyurethane

Diglycidyl 4,5-epoxy tetrahydro phthalate/methyl tetrahydrophthalic anhydride （TDE-85/MeTHPA） epoxy resin modified by polyurethane （PU） was prepared with 1,4-butanediol （1,4-BDO）, trimethylol propane （TMP） and polyurethane prepolymer synthesized by polypropylene glycol and toluene diisocynate. Chemical reaction and curing mechanism of this system were discussed by incorporating the results of infra spectrum analysis. The results indicate that the epoxy polymeric network I is obtained by the curing reaction between TDE-85 and MeTHPA, while the PU polymeric network II is obtained by the chain-extended and crosslinking reaction between 1,4-BDO, TMP and polyurethane prepolymer（PUP）. The graft chemical bonds are formed between polymer networks I and II that therefore increase the degree of blend and compatibility between epoxy polymer and PU.

Structural characteristics and properties of polyurethane modified TDE-85/MeTHPA epoxy resin with interpenetrating polymer networks

Diglycidyl-4,5-epoxycyclohexane-1,2-dicarboxylate(TDE-85)/methyl tetrahydrophthalic anhydride (MeTHPA) epoxy resin was modified with polyurethane(PU) and the interpenetrating polymer networks(IPNs) of PU-modified TDE-85/MeTHPA resin were prepared. The structural characteristics and properties of PU-modified TDE-85/MeTHPA resin were investigated by Fourier transform infrared(FTIR) spectrum,emission scanning electron microscopy(SEM) and thermogravimetry(TG). The results indicate that epoxy polymer network (Ⅰ) and polyurethane polymer network (Ⅱ) of the modified resin can be obtained and the networks (Ⅰ) and (Ⅱ) interpenetrate and tangle highly each other at the phase interface. The micro morphology presents heterogeneous structure. The integrative properties of PU-modified TDE-85/MeTHPA epoxy resin are improved obviously. The PU-modified TDE-85/ MeTHPA resin's tensile strength reaches 69.39 MPa,the impact strength reaches 23.56 kJ/m,the temperature for the system to lose 1% mass (t1%) is 300 ℃,and that for the system to lose 50% mass (t50%) is 378 ℃. Compared with those of TDE-85/MeTHPA resin,the tensile strength,impact strength,t1% and t50% of the PU-modified resin increases by 48%,115%,30 ℃,11 ℃,respectively. The PU-modified TDE-85/MeTHPA resin has the structure characteristics and properties of interpenetrating polymer networks.

DynamicMechanical and Chemorheology Analysis for the Blended Epoxy System with Polyurethane Modified Resin

As the important matrix material,epoxy resin has been widely used in the composites for various fields.On account of the poor toughness of epoxy resin limiting their suitability for advanced applications,considerable interests have been conducted to modify the epoxy resin to meet the engineering requirements.In this study,the bio-based polyurethane(PU)modified resin was adopted to modify the pure bisphenol-A epoxy by blending method with various proportions.Aiming to illuminate the curing behavior,mechanical and thermal properties,the blended epoxy systems were characterized by viscosity-time analysis,dynamic mechanical analysis(DMA)at different frequencies and temperatures,mechanical tensile test,thermogravimetric analysis(TGA)and Fourier transform infrared(FT-IR)spectroscopy.The results indicated that the introduction of PU modified epoxy was found to significantly inhibit the viscosity growth rates especially when the content of PU modified epoxy resin is higher than 60%.Notwithstanding the dynamic modulus and T_(g)reduced with the increment of PU modified epoxy,remarkable increment on the elongation at break was found and the flexibility was greatly promoted with the introduction of PU modified epoxy.The proportion of PU modified epoxy in the blends should be put balance considerations to obtain optimal mechanical properties.TGA results and FTIR spectrum demonstrated that the addition of PU modified epoxy did not change the thermal decomposition mechanism and chemical reaction mechanism,but the addition of PU modified epoxy inhibits the curing reaction of epoxy resin by measured and calculated the damping temperature domain
T from 35.7℃ to 48.9℃.

Synthesis and Characterization of Polyurethane and Epoxy Resin Interpenetrating Polymer Network

A series of Polyurethane (PU)/bisphenol A based Epoxy Resin(EP) Interpenetrating Polymer Networks(IPN) were synthesized and characterized by SEM, DSC, TGA and DMTA. It was found that IPN shows the best compatibility and damping properties when the ratio of PU/EP is 80 to 20. The results show that chain-extender and higher molecular weight of PPG are able to improve the properties of compatibility, damping and thermal properties.

聚氨酯改性环氧树脂/聚苯乙烯SIPNs固化动力学 (Ⅰ)环氧树脂固化剂含量对体系固化过程的影响

用化学滴定，粘度测定等方法，研究了环氧树脂固化剂（Ｔ３１）用量对聚醚型聚氨酯改性双酚Ａ型环氧树脂（ＰＵＤＧＥＢＡ）／聚苯乙烯（ＰＳｔ）室温同步ＩＰＮｓ体系固化动力学行为的影响。研究结果表明，增加Ｔ３１的用量，可以大大地缩短上述体系的凝胶时间。两个网络固化速度的峰值相对位置未改变。苯乙烯的固化受扩散控制，反应级数为２．０级；ＰＵＤＧＥＢＡ的固化为自动催化机理，反应级数为３．０级。

聚氨酯改性环氧树脂/聚苯乙烯室温同步固化IPNs的结构特征

用ＩＲ、ＤＳＣ及ＴＥＭ等手段，表征了聚醚型聚氨酯改性双酚－Ａ型环氧树脂（ＰＵＤＧＥＢＡ）／聚苯乙烯（ＰＳｔ）室温同步固化ＩＰＮ的结构。研究结果表明，所形成的固化产物，在３４２７ｃｍ－１处有强而宽的吸收，说明形成强的分子间氢键和较弱的分子内氢键。ＤＳＣ谱图只出现单一的转变，说明体系内两个组分的共混相容性较好；由于两个网络的固化速度基本同步，所形成的聚合物呈现界面较为模糊的双连续层状微相分离结构，层带宽度约１．０～２．０μｍ，层带中还有与之垂直重叠的亚片层结构，宽约０．１～０．２μｍ。

聚氨酯/丙烯酸酯/环氧树脂IPNS型胶黏剂的制备

以聚氨酯(PU)、环氧树脂E-51、甲基丙烯酸丁酯(BMA)为主要原料,使其形成互穿网络聚合物(IPNS),制得一种适用于动态条件下的胶黏剂。探究了不同质量分数的NCO、环氧树脂、丙烯酸酯对胶黏剂性能的影响。经过FTIR、DMA、力学性能等测试表明:体系中形成了互穿网络;胶黏剂的剥离强度、耐热性和耐水性提高,胶黏剂对NR/SBR基材的剥离强度达到4.6kN/m。

聚氨酯改性环氧树脂/聚苯乙烯IPNs的固化动力学Ⅱ苯乙烯含量对体系固化过程的影响

用化学滴定、粘度测定等方法,研究了苯乙烯含量对聚醚型聚氨酯改性双酚A型环氧树脂(PUDGEBA)/聚苯乙烯(PSt)室温同步半-IPN's(简称SIPN's)体系固化动力学的影响。结果表明,在上述所研究的体系中,苯乙烯含量的变化对凝胶时间有着不可忽略的影响。随苯乙烯含量的增加,凝肢时间明显延长。随苯乙烯含量的变化,两个组分固化反应反应速度最大值到来的时间可以相对提前或延后,甚至达到刚好同步。对上述体系两个组分固化动力学行为的计算机拟合结果表明:在转化率≤70％时苯乙烯的固化为扩散控制,呈现自动加速机理,反应级数为2.0;PUDGEBA的固化为自动催化机理,反应级数为3.0。

环氧树脂/聚氨酯IPNs注浆材料的同步法制备及其性能研究

采用开环合成环氧树脂预聚体接枝聚氨酯,研究制备了开环环氧树脂(EP-OH)/聚氨酯(PU)同步互穿聚合物网络(IPNs)注浆材料。对复合注浆材料的结构、力学性能、蓄热性能进行了表征。结果表明,部分开环的环氧树脂可有效提高材料的力学性能,拉伸强度达到74.3 MPa,冲击强度为10.3 KJ/m^2,粘接强度最高达10.4 MPa。当EP-OH添加量为20%时,复合注浆材料的最高蓄热温度由原样的142℃降至118℃。

聚氨酯/环氧树脂IPN的研究

综述了聚氨酯 /环氧树脂的IPN生成动力学与相分离过程 ,以及形态与性能 ,并介绍了聚氨酯

环氧树脂-丙烯酸酯IPN材料的合成与表征

用优化工艺合成环氧树脂－丙烯酸酯树脂的混合物乳液，在乳液中加入定量固化剂，形成了环氧树脂－丙烯酸酯ＩＰＮ材料。采用气相色谱（ＧＣ）测定乳液中的单体残留量，用凝胶渗透色谱（ＧＰＣ）证明乳液中环氧树脂的稳定存在。将最终形成的ＩＰＮ材料进行了力学性能和耐水性的测试分析，并以未形成ＩＰＮ结构的同组成样品的数据作对比，突出了该材料的优越性。最后，以热重分析（ＴＧＡ）和差示扫描量热分析（ＤＳＣ）的数据证明ＩＰＮ结构的形成有助于材料的玻璃化转变温度（Ｔｇ）和热分解温度（Ｔｄ）的提高。

EA/PU IPN灌浆材料的制备及性能

在自制的环氧丙烯酸酯(EA)及聚氨酯(PU)预聚体的基础上,制备环氧丙烯酸酯/聚氨酯互穿聚合物网络(IPN)化学灌浆材料,考察聚氨酯预聚体n(—NCO)/n(—OH)、聚氨酯预聚体用量、活性稀释剂用量、引发剂用量、促进剂用量、环境温度等对灌浆材料各方面性能的影响,同时分别采用红外光谱、扫描电子显微镜、热重-差热同步分析仪分析浆材固结体的官能团组成、拉伸断面微观结构及热稳定性。FT IR表征说明:IPN材料固化时发生聚氨酯预聚体的扩连反应及环氧丙烯酸酯与活性稀释剂的自由基共聚;SEM观察表明:IPN材料的拉伸断面出现韧性断裂特征,两网络之间的聚合与交联限制相分离;TG DTA曲线表明:IPN材料的热分解温度较高,耐热性能好。制得的聚氨酯预聚体n(—NCO)/n(—OH)为2.5:1,用量为15%时,IPN材料的各项性能达到最佳值,另外,可根据不同的灌浆要求,选择适宜活性稀释剂用量的灌浆材料,浆液胶凝时间可调。

一类 IPN 材料的抗蚀耐磨性能分析

本文从分子水平上对环氧树脂／聚氨酯（ＥＰ／ＰＵ）互穿形成的半ＩＰＮ材料的玻璃化转变温度、阻尼性能、力学性能、表面与断口形态特征进行了微相结构分析．结果表明：这类ＩＰＮ材料通过分子链的形变吸收、传递和耗散外应力，延缓了网络的疲劳破坏，因而具有良好的抗蚀耐磨性能．

聚碳酸酯型聚氨酯-环氧树脂IPN的性能及结构形态

由甲苯二异氰酸酯和聚六亚甲基碳酸酯二醇制备聚氨酯预聚体，再由该预聚体、双酚A环氧树脂等用同步法合成了聚碳酸酯型聚氨酯-环氧树脂互穿网络聚合物（PCPU－EPIPN）。红外光谱分析表明PCPU和EP两组分间存在一定的化学结合。差示扫描量热分析及热重分析研究表明：IPN在高温区存在单一玻璃化转变峰，当PCPU与EP的质量比mU／mE＝25／75时，IPN的Tg最高且热稳定性最好。透射电镜和扫描隧道显微镜研究表明，PCPU与EP的配比对IPN的形态结构有显著的影响。应力-应变测试发现：当mU／mE＝25／75时IPN体系力学性能最佳。

增韧环氧树脂/蓖麻油聚氨酯IPN的性能研究

研究了端羧基丁二烯-丙烯腈共聚物增韧环氧树脂(TER)与蓖麻油聚氨酯(PU)组成的互穿聚合物网络(IPN)的应力-应变行为、密度和溶胀行为。结果表明,在TER嵌段共聚物/PU(质量比)值为某一定值时,IPN表现出补强弹性体行为,它既有较高的强度,又有很高的伸长率,断裂能也达到最大值;IPN的密度高于按共混物加合法则计算的值,溶胀度则低于计算值,说明网络间存在着互穿。

丙烯酸酯、环氧树脂、聚氨酯半IPN结构性能的研究

聚酯多元醇218和二苯基甲烷二异氰酸酯(MDI)以预聚体法合成预聚物(A组分);另将甲基丙烯酸甲酯(MMA)和甲基丙烯酸丁酯(BMA)在70℃、偶氮二异丁腈(AIBN)引发下,在环氧树脂(E-51)内反应2h,再加入二甲硫基甲苯二胺(DMTDA),在120℃下反应2h得到扩链剂(B组分)。将A、B组分按照一定比例进行混合得到半互穿聚合物网络(IPN)结构的弹性体,考察其力学性能、耐温性能、耐水性及耐酸性。结果表明,当—NCO质量分数为7%、m(MMA+BMA)∶m(E-51)为1∶3.5、扩链剂中m(E-51)∶m(DMTDA)为1∶2.5时,试样拉伸强度最大为28.27MPa,剪切强度最大为6.25MPa;且有较好的耐水性和耐酸性。

IPN结构聚氨酯改性环氧树脂的性能研究

采用同步互穿聚合物网络技术制备了聚氨酯改性TDE-85/Me THPA环氧树脂体系,比较了环氧树脂TDE-85/MeTHPA固化体系改性前后力学性能和热稳定性的差异。研究结果表明,加入适量的由不同分子量聚醚二元醇合成的聚氨酯预聚体,对TDE-85/MeTHPA固化体系的力学性能、热稳定性均有所增加;当聚醚二元醇分子量为1000,且合成的聚氨酯预聚体加入量为15%时,同未改性的固化体系相比,该改性体系的拉伸强度和冲击强度分别上升48.0%和115%,分别达到69.39 MPa和23.56 kJ/m2,同时,该改性材料的热稳定性也有较明显的提高,其失重1%的温度T1%为300℃,比未改性的固化体系失重1%的温度高了30℃。

CSM/PBMA/EP三组分IPN形态及性能研究

本文用同步-分步结合的方法合成了氯磺化聚乙烯/聚甲基丙烯酸丁酯/环氧树脂(CSM/PBMA/EP)三组分IPN,对其形态及性能进行了研究。结果表明:随组成比的改变可以得到相容性不同的IPN,当CSM/PBMA/EP=40/40/20时,在动态力学谱上出现一个加宽的T_g转变峰;EP含量为9％时,得到相容性比较好的IPN。用分步染色的方法不仅可以观察三组分IPN的相区尺寸变化,也可以了解三相的相容程度。