聚氨酯/环氧树脂互穿网络聚合物硬质泡沫机械性能研究

采用同步法合成了聚氨酯/环氧树脂互穿网络聚合物(PU/EP IPN)硬质泡沫,对机械性能进行了研究。结果表明,与纯聚氨酯硬质泡沫相比,PU/EP IPN硬质泡沫的压缩强度和弯曲强度明显提高,在PU/EP IPN硬质泡沫中,随环氧树脂含量增加,PU/EP IPN硬质泡沫压缩强度和弯曲强度随之增大,当E-39D质量分数增加到24.2%时,PU/EP IPN硬质泡沫压缩强度和弯曲强度出现最大值;PU/EP IPN硬质泡沫机械强度随材料密度的增大而增加;随着环氧树脂中环氧值的增加,PU/EP IPN硬质泡沫的压缩强度、弯曲强度和拉伸强度均呈逐渐升高的趋势。     

聚碳酸酯型聚氨酯/环氧树脂互穿网络聚合物交联密度及力学性能

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)。红外光谱分析表明两组分间存在一定程度的化学结合。动态力学性能分析表明:由于两网络间的互穿、缠结以及接枝反应的发生,使体系中 PCPU 和 EP 的相容性得到改善。用溶胀法测定了 IPN 体系的交联密度,结果发现形成 IPN 后体系的交联密度相应比纯组分有所提高。力学性能测试表明:在 m(PCPU)/m(EP)=25/75处 IPN 体系的力学性能最佳。     

三元互穿聚合物网络弹性体的合成与性能

合成了以聚氨酯 (PU)为第一网络的三元IPN聚氨酯 /环氧树脂 /聚丙二醇二丙烯酸酯 (IPNPU/EP/PPGDA)互穿聚合物网络。分析了IPN的力学性能和萃取特性 ,结果表明 ,三元IPN的组成对力学性能和萃取特性有明显影响。该种弹性体具有优异的耐溶剂性 ,乙酸乙酯连续热萃取率仅为 5 %～ 11%。综合性能优异的三元IPN弹性体组成为m(PU) /m(EP) /m(PPGDA) =70 /2 5 /5 ,其机械性能为 :Ts=34 7MPa ,E =437% ,回弹性R =37%     

PU/EP/PPGDA三元IPN弹性体的结构研究

用红外光谱 (IR)、扫描电子显微镜 (SEM )、X光电子能谱 (XPS)研究了以聚氨酯 (PU)为第一网络的三元IPN聚氨酯 /环氧树酯 /聚丙二醇二丙烯酸酯 (IPNPU/EP/PPGDA)弹性体的互穿特性和形态结构。研究结果表明 ,各元素在三元IPN表面和内部分布不一致 ,表明三种聚合物在IPN中的分布是不均匀的 ,这种差异与IPN组成、组成聚合物间的相容性以及形态结构有密切联系     

接枝聚氨酯/环氧树脂/丙烯酸酯互穿网络聚合物的制备与性能

采用分步法制备了接枝聚氨酯(PU)/环氧树脂(EP)/丙烯酸酯(PA)互穿网络聚合物(IPNs),研究了不同接枝程度对聚合物热性能、动态性能以及黏接性能的影响。结果表明,PA与PU、EP互穿网络形成了接枝结构;热重分析(TGA)结果证实接枝IPNs的热稳定性明显优于非接枝IPNs;动态力学分析(DMA)显示,接枝能够使材料的相容性改善;黏接强度测试显示,当丙烯酸羟乙酯(HEA)质量分数为3%时,材料的T型剥离强度达到极大值4.6kN/m。     

环氧树脂改性聚氨酯体系非等温固化反应动力学

选用二异氰酸酯和端羟基聚丁二烯(HTPB)为主要原料,制备了端异氰酸酯基聚氨酯(PU)预聚体,通过共混法制备了聚氨酯(PU)/环氧树脂(E51)互穿网络聚合物(IPN)。通过非等温DSC法研究了PU/E51与MOCA固化剂的固化反应动力学,采用Vyazovkin非线性等转化率方法(NLV)求得活化能Ea,平均值为65.58 kJ/mol;通过Malek法进行模型拟合动力学分析,并求得了m、n、A值,得到动力学方程,同时进行了计算曲线与试验曲线拟合验证,拟合结果较好,符合?estak-Berggren(SB)模型。     

IPN中聚氨酯固化反应动力学的FTIR研究

用傅立叶变换红外光谱(FTIR)研究纯聚氨酯弹性体和聚氨酯/聚二甲基硅氧烷IPN中聚氨酯的固化反应动力学。结果表明,在PU/PDMS IPN体系中聚氩酯的交联反应仍为二级反应,聚二甲基硅氧烷的存在大大降低了PU/PDMS IPN的交联速率,并提高了反应活化能。     

受阻酚改性PU/PBMA IPN材料阻尼性能的研究

以聚碳酸酯二醇(PC-2000)、二苯甲烷二异氰酸酯(MDI)为原料合成聚氨酯(PU)预聚体,再以PU预聚体、扩链剂、甲基丙烯酸丁酯(BMA)及引发剂在一定条件下反应制备了聚氨酯/聚甲基丙烯酸正丁酯(PU/PBMA)互穿网络聚合物(IPN)材料,并加入受阻酚AO-80进行功能化改性,分别采用热固化法和室温固化法制备了受阻酚AO-80改性的PU/PBMA IPN材料。讨论了固化方法、PU与PBMA的配比、受阻酚AO-80用量等对IPN材料阻尼性能的影响,通过动态机械热分析、热失重分析以及扫描电子显微镜对IPN材料的阻尼性能、热稳定性和微观形态结构进行表征。结果表明,热固法比室温固化法更有利于制备高性能阻尼材料;受阻酚AO-80的加入可以明显提高IPN材料的阻尼性能,并能够有效地拓宽阻尼温域;当PU与PBMA质量比为60/40、AO-80质量分数为28%时,所制备的IPN材料的阻尼性能最佳。     

聚醚聚氨酯／聚甲基丙烯酸甲酯互穿聚合物网络相容性的研究

用同步法合成了聚醚聚氨酯/聚甲基丙烯酸甲酯(PU/PMMA)互穿聚合物网络(IPN)。讨论了不同交联缠结程度对IPN形态及性能的影响,分析了影响IPN两网络相容性的热力学及动力学因素。增加网络的交联密度可有效地改善IPN网络间的相容性,同时,调节两网络生成速度基本同步,控制在热力学相分离发生前使两网络最大程度地互穿缠结,也能减小相分离的程度,改善IPN网络间的相容性。     

聚氨酯／乙烯基酯树脂互穿聚合物网络合成动力学及相容性

以丙烯酸乙酯为乙烯基酯树脂的共聚单体,利用“同步互穿”工艺室温固化制备了一系列聚氨酯／乙烯基酯树脂互穿聚合物网络 (PU/VER IPN).对IPN固化过程的动态跟踪及半定量考察的结果表明：由于两网络不同的聚合机理及体系黏度的影响,PU网络先形成,网络形成得较完善.采用示差扫描量热仪 (DSC)、原子力显微镜 (AFM)及透射电镜 (TEM)定性考察了IPN两网络间的相容性,结果表明：形成的双相连续“同步互穿”体系的相畴尺寸在纳米级范围,当PU 和VER的组成比为80/20和70/30时体系均出现一个玻璃化转变温度 (T_g),较好地改善了PU与常规VER树脂的相容性.进一步通过DSC实测和理论T_g值的计算获得相容因子 (θ),定量考察了两网络间的相容性.     

Synthesis and characterization of nanocomposites of silicon dioxide and polyurethane and epoxy resin interpenetrating network

Nanocomposites with varying concentrations of nanosized silicon dioxide particles were prepared by adding nanosilica to interpenetrating polymer networks (IPN)s of polyurethane and epoxy resin (PU/EP). The PU/EP IPNs and nanocomposites were studied by dynamic mechanical analysis, scanning electronic microscopy, wide‐angle X‐ray diffraction and small‐angle X‐ray scattering. The result showed that adding nanosize silicon dioxide can improve the properties of compatibility, damping and phase structure of IPN matrices. Copyright © 2003 Society of Chemical Industry     

Reinforcement of polyurethane/epoxy interpenetrating network nanocomposites with an organically modified palygorskite

An organophilic palygorskite (o‐PGS) prepared by the treatment of natural palygorskite with hexadecyl trimethyl ammonium bromide was incorporated into interpenetrating polymer networks (IPNs) of polyurethane (PU) and epoxy resin (EP), and a series of PU/EP/clay nanocomposites were obtained by a sequential polymeric technique and compression‐molding method. X‐ray diffraction and scanning electron microscopy analysis showed that adding nanosize o‐PGS could promote the compatibility and phase structure of PU/EP IPN matrices. Tensile testing and thermal analysis proved that the mechanical and thermal properties of the PU/EP IPN nanocomposites were superior to those of the pure PU/EP IPN. This was attributed to the special fibrillar structure of palygorskite and the synergistic effect between o‐PGS and the IPN matrices. In addition, the swelling behavior studies indicated that the crosslink density of PU/EP IPN gradually increased with increasing o‐PGS content. The reason may be that o‐PGS made the chains more rigid and dense. As for the flame retardancy, the PU/EP nanocomposites had a higher limiting oxygen index than the pure PU. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of polyurethane/epoxy interpenetrating network nanocomposites with organoclays

Summary Novel nanocomposites with varying contents of organophilic montmorillonite (oMMT) were prepared by intercalating oMMT to interpenetrating polymer networks (IPNs) of polyurethane and epoxy resin (PU/EP). The PU/EP networks and the oMMT modified PU/EP IPNs nanocomposites were studied with Fourier transform infrared spectrometry, scanning electronic microscopy, transmission electronic microscopy, wide-angle X-ray diffraction, water absorption and tensile test. The results show that oMMT and the IPNs of polyurethane and epoxy resin exhibit synergistic effect on the phase structure and morphology of the IPNs nanocomposites. The addition of oMMT to the PU/EP IPNs matrix provides two fold benefits to the properties of the IPNs nanocomposites. oMMT has not a distinct effect on chemical structure of PU/EP IPNs but promotes the compatibility and phase structure of the IPNs, and the forced compatibility of PU and EP in interpenetrating process improves the dispersion degree of oMMT. Both the mechanical properties and water resistance of the PU/EP IPNs nanocomposites are superior to those of the pure PU/EP IPNs.     

Synthesis of biodegradable PU/PEGDA IPNs having micro-separated morphology for enhanced blood compatibility

Summary New biodegradable hydrophobic polyurethane (PU)/hydrophilic poly (ethylene glycol) diacrylate (PEGDA) IPN was simultaneously synthesized with changing the molecular weight of PEGDA to investigate the effect of crosslinking density on the degree of phase separation. PU was modified using biodegradable poly(-caprolactone)diol and the hydroxy group of PEG was substituted to crosslinkable acrylate group having double bond, which induce photo-polymerization. The sturucture of PEGDA was confirmed by NMR. Because the reaction rate of PEGDA was faster than that of PU, the continuous matrix of the micro-separated PU/PEGDA IPNs having amphiphilic character was made of hydrophilic PEGDA-rich phase. All IPNs have sea-island morphology resulting from the suppressed phase separation. The effect of the degree of phase separation on blood compatibility was investigated.     

Studies on castor oil–based polyurethane/polyacrylonitrile interpenetrating polymer network for toughening of unsaturated polyester resin

Tricomponent interpenetrating polymer network (IPN) systems involving castor oil, toluenediisocyanate (TDI), acrylonitrile (AN), ethylene glycol diacrylate (EGDA), and general‐purpose unsaturated polyester resin (GPR) were prepared with various compositions. The structures of the IPNs at various stages were confirmed using FTIR. The thermal stability of the IPNs was studied using TGA, which indicated that the polyurethane/polyacrylonitrile/GPR (PU/PAN/GPR) IPN underwent single‐stage decomposition, showing perfect compatibility at the IPN composition of 10 : 90 (PU/PAN : GPR). The mechanical properties such as tensile, flexural, impact, and hardness for the IPNs with various compositions were determined. It was found that the tensile strength of the GPR matrix was decreased and flexural and impact strengths were increased upon incorporating PU/PAN networks. The swelling properties in water and toluene were also studied. The morphology of the IPNs was studied using SEM. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 817–829, 2004     

Effect of crosslinking density on the physical properties of interpenetrating polymer networks of polyurethane and 2-hydroxyethyl methacrylate-teminated polyurethane

Interpenetrating polymer networks (IPNs) of 2-hydroxyethyl methacrylate-terminated polyurethane (HPU) and polyurethane (PU) with different crosslinking densities of the PU network were prepared by simultaneous solution polymerization. Dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC) show that compatibility of component polymers in IPN formation depends on the crosslinking density of the PU network. Physical properties such as density and water absorption rely on the subtle balance between the degree of phase separation and the crosslinking density of the PU network. In spite of the occurrence of phase separation, the tensile moduli and tensile strength of the IPNs increase with the crosslinking density of the PU network. Morphological observation by scanning electron microscopy revealed different fracture surfaces between the compatible and incompatible IPNs. Surface characteristics of the IPNs, indicated as hydrogen bonding index and hard-to-soft segment ratio, are altered considerably by varying surface morphologies. Improved blood compatibility of IPN membranes is due to the variation of the hydrophilic and hydrophobic domain distribution.     

Tribological mechanism improving the wear resistance of polyurethane/epoxy interpenetrating polymer network via nanodiamond hybridization

The excellent synergistic effect of physical/mechanical properties of polyurethane/epoxy (PU/EP) interpenetrating polymer network (IPN) and the validity of nanofilling have one potential to improve the wear resistance of polymeric materials. With the aim of practical application, PU/EP IPN nanocomposites are prepared with nanodiamond (ND) as a reinforcing additive. Results showed the uniform thermal stability and the excellent compatibility between PU and EP in ND‐hybridized PU/EP IPN. Simultaneously, ND particles work as crosslinked points improving the physical/mechanical properties of ND‐hybridized PU/EP IPN, especially the wear resistance. The measurement of tribological property and the scanning electron microscope indicated that the wear resistance is able to be improved a lot by the formation of IPN and by the addition of ND. Consequently, the tribological mechanism of PU/EP IPN nanocomposites comes into being. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40244.     

Morphologies and Mechanical Properties of Polyurethane/Epoxy Resin Interpenetrating Network Composites Modified with Kaolin

Polyurethane/epoxy resin (PU/EP)/dimethyl sulfoxide modified kaolin (PU/EP/K-DMSO) interpenetrating network composites were prepared by in situ intercalation method. FT-IR showed that hydrogen bonding existed between kaolin and PU/EP matrix. The structure of composites was characterized by XRD, SEM and TEM. The result indicated that: K-DMSO by a nanometer size and homodisperse in the PU/EP matrix. The analysis of images obtained by polarizing microscope showed that bubble diameter has decreased with the K-DMSO added. Mechanical test results indicated that: the tensile and compression strength of the PU/EP/K-DMSO composites are superior to those of the PU/EP IPNs.