梯度温度场对聚氨酯微相分离程度的影响

将聚氨酯的固化反应引入到可控的梯度温度场中进行,制备了厚度方向具有梯度结构的高分子材料.利用红外光谱和差示扫描量热法对所制备材料的微相分离程度进了表征.结果表明,从固化温度较高的一端到较低端,聚氨酯的微相分离程度逐渐降低.利用扫描电镜进行的微观形貌分析也证明了这一结论.对差示扫描量热法测试数据进行了分析讨论,探讨了梯度...     

水分对聚氨酯微孔弹性体工艺性能及结构的影响

采用一步法制备聚氨酯微孔弹性体材料,考察了聚醚组分中水分对聚氨酯微孔弹性体工艺、性能及微观结构的影响。结果表明,随着聚醚组分中水分含量的增加,聚合反应乳白时间、凝胶时间延长;材料的硬度先略微升高,之后缓慢下降;材料的密度、挠曲模量、拉伸强度、断裂伸长率均是先缓慢下降,之后下降显著;材料的发泡趋势更加明显,泡孔数增多,泡孔间距缩短。     

聚碳酸酯二元醇改性的聚氨酯微孔泡沫的研制

将聚碳酸酯二元醇(PCDL)作为配方组分,采用直接添加和将PCDL与异氰酸酯合成预聚体后再添加的不同工艺,制备了聚碳酸酯型聚氨酯微孔泡沫,并分别与普通聚氨酯微孔泡沫进行了对比.结果表明,聚碳酸酯型聚氨酯微孔泡沫的力学性能比普通聚氨酯微孔泡沫有所提高;PCDL预聚体制备的聚氨酯微孔泡沫材料耐热老化性能最佳.     

梯度固化聚氨酯弹性体的结构与性能

用梯度固化的方法制备了梯度固化聚氨酯弹性体材料,用红外光谱以及力学性能测试等手段对所制备样品进行了表征。结果表明,沿着高温到低温的方向,梯度固化聚氨酯弹性体的微相分离程度梯度减弱,材料的杨氏模量逐渐降低,透明度则逐渐提高。     

P—715聚氨酯微孔塑料抛光片的研究

P—715聚氨酯微孔塑料抛光片系由多元醇与异氰酸酯制备的预聚体,在发泡剂、催化剂及磨料等存在下,经化学反应而制得的具有微孔结构的高分子材料。并经专用刀具加工成一定厚度的薄片。     

梯度聚氨酯脲弹性体的制备与性能研究

采用温度梯度固化的方法制备具有梯度结构的聚氨酯脲弹性体，并对其结构和性能进行研究。结果表明，从高温区到低温区，聚氨酯脲弹性体微相分离程度呈梯度减弱，弹性模量逐渐减小，拉伸强度总体呈增大趋势，拉断伸长率逐渐增大。     

PTMG/TDI聚氨酯梯度固化的红外光谱分析

采用梯度温度场固化的方法,制备得到了PTMG/TDI(聚四亚甲基醚二醇/甲苯二异氰酸酯)聚氨酯弹性体,并使用红外光谱对所制备的试样进行了研究分析。研究结果表明:从高温一侧到低温一侧,聚氨酯弹性体的微相分离程度呈现梯度渐变的特点;固化剂的用量、温度梯度、预固化时间以及物料的温度都会直接影响聚氨酯弹性体微相分离程度的梯度。     

聚氨酯功能梯度材料的研究现状与展望

简介了聚合物梯度材料的发展概况,并着重综述了聚氨酯功能梯度材料的研究进展。     

保温工程用聚氨酯硬质泡沫材料的制备研究

采用一步法制备了聚氨酯硬质泡沫材料,通过改变原料组分中聚醚的组成、异氰酸酯指数、阻燃剂用量、水的用量、交联剂的种类,分别考察了其对双组份聚氨酯硬质泡沫材料性能的影响。结果表明,组合聚醚羟值黏度对制品性能起关键作用,化学发泡剂水的添加量需要严格控制,提高液态添加型阻燃剂含量能够提高制品氧指数,但同时会降低制品力学性能,三乙醇胺作为交联剂制品综合性能好。制备得到了最佳的组合配方,制备出了硬度大、尺寸稳定性好、性能优异的聚氨酯硬质泡沫材料,完全可以应用在保温工程的施工作业中。     

锂离子电池正极材料LiNi1/2Co1/6Mn1/3O2的制备与性能

采用Co2+浓度递增的金属离子混合溶液分次共沉淀方法制备Ni1/2Co1/6Mn1/3(OH)2,以其为前驱体,通过高温固相反应得到具有Co含量梯度的层状LiNi1/2Co1/6Mn1/3O2,探讨了焙烧温度及Co含量梯度对材料的结构和电化学性能的影响. 通过X射线衍射、扫描电镜、热重分析及恒电流充放电测试对合成的样品进行了表征. 结果表明,700℃合成产物即具有类LiNiO2的六方层状结构,800和850℃合成产物阳离子排列有序度高,层状结构显著. 材料结晶度好,粒度均匀,粒径在亚微米级. 合成温度800℃的梯度材料具有最佳的电化学性能, 2.5~4.2 V, 0.1 C倍率充放电50次后,梯度材料的容量仍保持在171.2 mA×h/g. 相同的焙烧温度,梯度材料比均匀材料的电化学性能更加优异.     

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     

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。     

聚氨酯/环氧树脂互穿网络聚合物反应动力学

通过共混法制备了聚氨酯(PU)/环氧树脂(EP)互穿网络聚合物(IPN),采用示差扫描量热法(DSC)和动态机械分析(DMA)对IPN形成过程中的固化反应动力学及产物IPN的相容性进行了研究,结果表明,m(PU)/m(EP)=10∶6的IPN体系的反应级数为0.95,表观活化能为169.23 kJ/mol;PU/EP IPN只有1个玻璃化转变温度,相容性好。     

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.     

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     

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     

PU/EP共混物中的化学反应及粘接性能的研究

合成聚氨酯（PU）预聚体同环氧树脂（EP）共混,加入扩链剂、交联剂,制得PU／EP复合材料,用红外光谱分析研究了共混体系中的化学反应,考察了两聚合物组成对聚合物网络间互穿程度的影响,研究了共混物的粘接性能。     

Preparation and Characterization of Electroconductive Adhesives of NanoG/Polyurethane-Epoxy IPNs

Polyurethanes (PU) based on toluene diisocyanate (TDI) and polypropylene glycol 2000 (PPG) were reacted with an epoxy resin (EP) to prepare interpenetrating polymer networks (IPNs). Three kinds of electroconductive adhesives were prepared by dispersing nano-graphite (NanoG) into different matrices, i.e., pure PU, crosslinked PU/EP, and pure EP. The effects of epoxy content on morphological structure, conducting properties, thermal stability, and adhesive properties of the electroconductive adhesives were investigated by Fourier transform infrared spectroscopy, scanning electron microscopy, standard digital multimeter, dynamic mechanical thermal analysis, and lapshear tests. The results indicate that epoxy in the polyurethane-epoxy IPN adhesives plays an important role in clanging the morphological structure and improving conductivity properties, thermal stability, and adhesive properties of the electroconductive adhesives of PU.     

混合大二醇基聚氨酯弹性体/环氧树脂互穿网络聚合物的研究

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)混合大二醇作为软链段,首先通过两步溶液聚合法合成了-NCO封端的混合大二醇基聚氨酯(PU)弹性体预聚物(PUT);然后以PUT和环氧树脂(EP)预聚物为原料、1,3-双(γ-氨丙基)-1,1,3,3-四甲基二硅氧烷(BATS)为交联剂,采用同步溶液聚合法合成了PUT/EP互穿聚合物网络(PUT/EP I PN)。使用傅里叶红外光谱(FT-I R)法、动力学分析(DMA)法和扫描电子显微镜(SEM)法,对PUT和PUT/EP I PN进行分析和表征,并对其力学性能和表面疏水性进行测试。实验结果表明,PUT/EP I PN中不存在宏观相分离状态,仅发生微观相分离状态;当PUT/EP I PN中w(PUT)=50%时,PUT/EP I PN具有优异的综合力学性能和表面疏水性。     

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%