不饱和聚酯片状模塑料的研究

采用聚氨酯预聚物作增稠剂对带端羟基的不饱和聚酯进行增稠,制备出一种新型的不饱和聚酯片状模塑料(SMC),并研究了其增稠性能、增韧性能及贮存稳定性。结果表明,增稠剂PU400的用量要控制在8％～10％,否则树脂糊无法正常浸渍玻璃纤维;不饱和聚酯SMC的体积收缩率随PU400加入量的增加而明显变小;当PU400含量为36％,时,不饱和聚酯SMC固化物的拉伸强度、断裂伸长率、冲击强度都维持在一个较高的水平;该不饱和聚酯SMC有良好的贮存稳定性。     

SMC中不饱和聚酯树脂增稠及贮存性能的研究

本文以甲苯二异氰酸酯（TDI）及其预聚物PU400、PU200为增稠剂对端羟基的不饱和聚酯进行增稠，通过树脂的粘度变化、螺线流动实验对这种新型增稠体系的增稠性能和片材的贮存稳定性进行了研究。并与以MgO为增稠剂的片材进行了对比研究，结果表明：（1）异氰酸酯预聚体的增稠性能优于异氰酸酯单体。（2）增稠剂PU400的质量百分数Wpu应该小于10％。在相同的－NCO浓度下，不饱和聚酯树脂的增稠速度随分子量的提高而加快；在273K下，不饱和聚酯树脂能在4天内完成增稠，在323K下，能在8小时内完成增稠。（3）聚酯片材贮存三个月后，由异氰酸酯增稠体系制备的片材的螺线长度，低于氧化镁增稠体系的下降幅度。     

PPG相对分子质量对PPG/PAPI预聚体改性UPR性能的影响

采用摩尔比为3:1的多苯基多次甲基多异氰酸酯(PAPI)与聚丙二醇(PPG)合成了活性端基聚氨酯(PU)预聚体,并与自制端羟基不饱和聚酯树脂共混改性,制得改性不饱和聚酯树脂(UPR).研究了不同相对分子质量的PPG对改性UPR粘度的影响;研究了PPG相对分子质量对改性UPR力学性能的影响;利用SEM对改性UPR冲击断面...     

异氰酸酯改性不饱和聚酯树脂的研究

用异氰酸酯类与蓖麻油改性的端羟基不饱和聚酯树脂(UPR)进行共混。结果表明，三羟甲基丙烷甲苯二异氰酸酯／UPR的质量比例在0．5～0．9之间力学性能最优；聚酯的双键密度增加，抗拉强度增大，断裂伸长率减小；不同种类的异氰酸酯同端羟基不饱和聚酯树脂共混，力学性能差别比较大；促进剂N，N-二甲基苯胺含量对树脂凝胶时间影响比较大，而二丁基月桂酸锡含量对树脂凝胶时间影响不明显。     

H_(12)MDI型端硅烷基聚氨酯预聚物的合成

以H12MDI(4,4′-二环己基甲烷二异氰酸酯)和不同Mr(相对分子质量)的PPG(聚丙二醇醚)为原料、DBTDL(二月桂酸二丁基锡)为催化剂和A1170[双-(γ-三甲氧基硅丙基)胺]为封端剂,合成了SPU(端硅烷基聚氨酯)预聚物。研究结果表明:SPU预聚物的合成包括PU预聚物的合成和封端反应两个阶段;PU(聚氨酯)预聚物的合成反应速率随催化剂用量增加而加快,当催化剂用量约为50 mg/kg、反应温度为80℃和反应时间为4 h时,PU预聚物的合成反应可基本完成;封端反应的最佳温度为70℃,反应3 h后体系—NCO含量可降至0;通过调节R值[即n(—NCO)/n(—OH)]和PPG的Mr,可使SPU预聚物的黏度控制在56.70~229.92 Pa·s范围内。     

PF用低收缩添加剂的研究

通过调整物料配比合成了端羟基封端和端羧基封端的聚氨酯 (PU)预聚物 ,并分别与酚醛树脂 (PF)固化 ,制备了两种低收缩体系的复合物 ,利用红外光谱对其结构进行表征。通过测试固化物的体系收缩率表明 :随着聚氨酯预聚物加入量的增加 ,PF/PU共混物的体积收缩率明显变小 ,并能达到负值。端羧基PU的低收缩性能更为显著 ,当其加入量在 5 相似文献   

端羟基聚丁二烯橡胶对水性聚氨酯性能的影响

主要探讨了端羟基聚丁二烯橡胶(HTPB)对水性聚氨酯(WPU)耐水性、力学性能、胶膜手感的影响,以及不同交联剂对胶膜的影响。     

端丙炔酯基环氧乙烷四氢呋喃无规共聚醚的合成与性能研究

为了提高端炔基反应活性,以端羟基环氧乙烷-四氢呋喃无规共聚醚(PET)为原料,通过酯化反应制备得到了端丙炔酯基环氧乙烷-四氢呋喃无规共聚醚(PTPET)。采用红外光谱、核磁、GPC与黏度测试对所得产物进行了测试与表征,基于理论计算PTPET端炔基值,并在非催化条件下制备得到聚三唑交联聚醚弹性体,对弹性体力学性能进行了初步表征。红外光谱分析表明,PTPET分子结构中端羟基吸收峰消失,同时出现丙炔酸酯基的炔基、羰基红外特征吸收峰。¹³C-NMR分析表明,PTPET谱图中与羟基相连碳原子的共振吸收峰彻底消失,出现羰基结构中碳原子的特征共振峰,PET端基酯化反应完全。PET端基酯化并未引发聚合物断链、扩链等副反应,所得PTPET较PET具有较高的黏度。室温下,R值为1时,弹性体拉伸强度为0.89MPa,断裂伸长率为189%,力学性能良好。成功制备了数均分子量4000左右、端基转化完全、理论炔值为0.425mmol/g的端丙炔酯基聚醚,并通过无催化条件下制备弹性体证实了反应活性的提高。     

高顺式HTPB对不饱和树脂的改性

针对不饱和聚酯脆性大的问题,以高顺式端羟基聚丁二烯(HTPB)为改性剂,采用溶液共缩聚法制得一系列不同HTPB质量分数的不饱和聚酯树脂(UPR),考察它们交联固化产物的力学性能和热性能.结果表明,无论常温或低温下,改性UPR的断裂伸长率、拉伸强度和冲击强度均高于纯UPR的对应值.当HTPB质量分数为5％ 时,改性UPR...     

甲基丙烯酸B酯改善以HTPB为基聚氨酯互穿聚合物网络的工艺性能与力学性能

以聚甲基丙烯酸B酯(BM A)为塑料相,以端羟基聚丁二烯(HTPB)为基的聚氨酯(PU)为橡胶相合成了多种配方的互穿聚合物网络(IPN)胶片。测定了预聚物的黏度,发现预聚物黏度可降低到0.500 Pa.s以下,加入丙烯酸酯后,其工艺性能得到改善。测试结果表明,改进工艺后胶片的拉伸强度达1.432M Pa,断裂伸长率达576.614%。丙烯酸酯对胶片力学性能的改善效果著显。     

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.     

Compatibility of poly(vinyl chloride) and polyurethane blends

The compatibility and the mechanical properties of the blends of polyurethane (PU) elastomer and poly(vinyl chloride) (PVC) were studied. The results showed partial compatibility between PU and PVC. When the portion of PVC in blends exceeded 75%, the compatibility decreased. On the other hand, increasing the molecular weight of the glycol in PU improved the compatibility. The elongation decreased and the Young's modulus increased as the proportion of the weight of PVC in blends was increased. The tensile strength reached a minimum when PU/PVC was 50/50.     

PVA对碳酸钙、淤泥/不饱和聚酯树脂体系增强的探讨

采用聚乙烯醇(PVA)对碳酸钙、淤泥进行改性并将其作为不饱和聚酯树脂填料。研究了PVA掺量对碳酸钙/不饱和聚酯树脂和淤泥/不饱和聚酯树脂体系力学性能的影响。采用IR、DSC和SEM探讨了PVA对这2类体系的改性机理。实验结果表明:加入5%PVA后,碳酸钙/树脂体系,淤泥/树脂体系弯曲强度分别提高了55.3%和58.4%。PVA对2种体系的改性增强效应均源于PVA与填料和树脂之间氢键的桥梁作用,氢键改善了无机填料与树脂的相容性,这与以往改性剂与碳酸钙反应生成酯酸钙固化物的机理是不同的。     

聚氨酯-聚丙烯酸酯复合乳液的动态力学性能

采用种子乳液聚合法合成了聚氨酯一聚丙烯酸乙（丁）酯[PU／PE（B）A]复合乳液。并研究了不同组成对复合乳液性质、相客性、阻尼性能及拉伸性能的影响。耐水性及稳定性测试表明，随PE（B）A含量的增加，涂膜的耐水性变好，而乳液的稳定性变差。动态力学性能测试（DMS）表明，合成的PU／PE（B）A复合乳液为半相容体系，其相容性随PE（B）A含量的增加而增强。DMS和拉伸试验表明PU／PEA／P（B）A（质量比50／25／25）复合乳液具有优良的阻尼性能、抗拉强度和断裂伸长率，可用作宽温域阻尼涂料。     

The Influence of Macromolecular Structure and Composition on Mechanical Properties of Films Cast from Solvent‐Free Polyurethane/Acrylic Hybrid Dispersions

Polyurethane (PU) /acrylic dispersions are of great commercial interest due to the synergetic combination of the PU and acrylic polymers. In this work, a series of PU/acrylic dispersions is synthesized by a solvent‐free technique and the influence of colloidal structure, grafting between the two polymers, and the nature of the two polymer phases themselves on the mechanical properties of films cast from the dispersions is explored. TEM analysis shows that the particles have a PU shell/acrylic core structure which is translated into the morphology of films cast from the dispersions. This particle/film morphology leads to the acrylic copolymer acting as a filler material and allows high T_g copolymers to be employed, leading to films with very high mechanical strength. Grafting of the PU and acrylic phases leads to increased compatibility but has little effect on the mechanical properties which are largely determined by the hardness of both the diol used in the PU synthesis and more importantly the acrylic (co)polymer composition. This work allows us to propose a series of design principles in order to synthesize PU/acrylic hybrids with controlled mechanical properties.     

Studies on interpentrating polymer networks of polyurethane and polybismaleimide. I. Polyurethane and bismaleimide-urethane copolymer

The interpenetrating polymer networks (IPNs) of polyurethane (PU) and the mixture of bismaleimide (BMI) and the 2-hydroxylethyl methacrylate (HEMA)-terminated PU prepolymer (HPU) were prepared by using a simultaneous polymerization technique. The effects of the PU molecular weight and the amounts of the PU on the mechanical properties, thermal stability, and dynamic mechanical properties are discussed. The IPNs exhibited superior ultimate tensile strength as the polyol of PU and HPU in the IPNs is based on poly(tetramethylene oxide) (PTMO) glycol of molecular weight 1000 (PTMO1000). Izod impact property of the IPNs indicated that the PU(PTMO1000)/BMI-HPU(PTMO1000) IPNs had much more significant improvement than that of the PU(PTM02000)/BMI-HPU(PTMO2000) IPNs. Better thermal stability was shown by the IPNs as compared with the components of the networks, i.e. PU or BMI-HPU copolymers. The dynamic mechanical analysis (DMA) indicates that these IPNs show various shifts in the loss moduli(E) at the high and low temperature transition peaks for various molecular weight of the polyol employed in the PU. Better compatibility between BMI and PU was found as the PU(PTMO1000) was employed.To whom all correspondence should be addressed.     

Properties of copolymer-type polyacetal/polyurethane blends

Mechanical and physical properties of the blends of copolymer-type polyacetals (POM) with polyurethane (PU) were investigated. The properties relationships of POM/PU blends are established by studying their morphology and compatibility. For the blends rich in POM, the morphology of the blends observed with a scanning electron microscopy (SEM) indicates that the blends containing lower than 50 wt % (46 vol %) PU are almost completely filled with spherical particles of the dispersed PU. As the concentration of PU increases, the spherulites of the POM observed by SEM become less perfect with coarse fine structure. Furthermore, when the concentration of PU was increased up to 50 wt %, the spherulties of POM in the blends are smaller than those of unblended POM. X-ray diffraction studies reveal that the degree of crystallinity of POM decreases with increasing PU content, which is nonmonotonic. This conclusion agrees with the observations made by differential scanning calorimetry (DSC) and density measurements. For the blends rich in POM, mechanical properties show that the impact strength of POM/PU blends increased with decreasing spherical size of the dispersed PU.     

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.     

Effect of using sepiolite silicate + fumed silica mixtures as fillers on the characteristics of solvent-based polyurethane adhesives

Abstract —Both fumed silica and sepiolite have been used as a filler of polyurethane (PU) adhesives. Although effective, the small particle size and the relative high cost of fumed silica are limitations in some applications. Sepiolite is cheaper than fumed silica, but its relatively large particle size facilitates its settling from the adhesive solutions. In this study, the usefulness of using sepiolite + fumed silica mixtures as a filler in solvent-based PU adhesives is demonstrated. The rheological and adhesion properties of the PU adhesive solutions and the rheological and mechanical properties of the PU films (without solvent) were studied. SEM micrographs of PU films showed the morphology and compatibility of the fillers with the PU matrix. The use of sepiolite + fumed silica mixtures inhibited the settlement of the filler from the PU adhesive solutions, increased both the storage and the loss moduli, and improved the rheological and mechanical properties of the PU. On the other hand, the green (immediate) T-peel strengths of roughened styrene-butadiene rubber/PU adhesive joints and plasticized PVC/PU adhesive joints were greatly improved in filled PU adhesives. The effects produced by using fumed silica alone or sepiolite + fumed silica mixtures were very similar, although in general, somewhat more marked in fumed silica-filled PU.