聚氨酯/环氧梯度互穿网络聚合物微观形貌及力学性能研究

设计了一种新的梯度组分分布数学模型,采用梯度因子和梯度层数控制梯度组分的分布,并采用逐层浇铸的方法制备了聚氨酯(PU)/环氧(EP)梯度互穿网络聚合物(IPNs)材料,研究了其微观形貌和力学性能.研究结果表明,随着梯度组分舍量沿梯度方向的变化,不同梯度单层的相结构和断裂特性也呈现相应的变化,逐渐由分散相向连续相转变.从中心层到表面层,梯度单层的弯曲模量逐层降低,挠度逐层增大,梯度IPNs的弯曲强度和模量低于普通IPNs,抗冲击性能高于普通IPNs.     

结构变化对梯度互穿网络聚合物力学性能影响的研究

设计了一种新的梯度组分分布数学模型,采用梯度因子和梯度层数控制梯度组分的分布,研究了梯度结构变化对梯度IPNs力学性能的影响.结果表明,梯度层数越多,梯度IPNs的拉伸性能和抗冲击性能越优异,随着梯度因子的增加,梯度IPNs的拉伸性能先平缓增加,当梯度因子过高时,梯度IPNs的拉伸性能显著下降,梯度IPNs的抗冲击性能随着梯度因子先显著增加,然后平缓变化.梯度IPNs的力学性能优于普通IPNs.     

FTIR研究预辐照PMMA／PU IPNs的反应动力学

借助于~(60)Co-γ射线对MMA进行辐照预聚合,用FTIR研究了预聚合MMA/PU IPNs的反应动力学,讨论了反应温度、交联剂含量对IPNs反应动力学的影响。结果表明,IPNs中各组分按互不干扰的机理进行,根据PU反应速率明显快于PMMA网络的事实,提出了PU网络的“笼子效应”。     

聚醚型聚氨酯/环氧树脂互穿网络聚合物的结构与性能研究

以4,4’-二苯基甲烷二异氰酸酯和聚醚及双酚A型环氧树脂为原料经共聚合成了聚氨酯(PU)/环氧树脂(EP)互穿聚合物网络(IPNs).通过改变聚氨酯结构及环氧树脂含量制备系列PU/EP的IPNs,并对其性能进行了研究.研究表明随着聚氨酯中两官能度聚醚用量增加,IPNs体系的亲水性增强、表面自由能增大;此外随着环氧树脂含量增多,整个IPNs体系的疏水性增强;力学性能测试表明,聚氨酯结构以及环氧树脂含量对PU/EP的IPNs材料力学性能影响较大.     

丙烯酸改性PU/PMMA接枝型半IPNs的制备及其力学性能研究

采用“同步”法制备了丙烯酸改性聚氨酯与聚甲基丙烯酸甲酯互穿的接枝型聚合物网络（IPNs)体系，通过红外光谱跟踪检测了其固化过程，用TEM对所形成的多相体系形貌进行了检测，并对不同软／硬组成比及交联密度的IPNs材料的力学性能进行了测试。在此基础上，从IPNs体系网络间的互穿缠结作用角度对检测结果进行了讨论。结果表明，IPNs所形成的复相体系中接枝结构的存在可使组分在较宽范围内发挥良好的协同作用，这为从分子设计及工艺设计两角度获得性能优异的功能材料提供了借鉴。     

氧化海藻酸钠交联海藻酸钙/明胶(半)互穿网络的制备及性能

以自制的氧化海藻酸钠为交联剂,制备了海藻酸钙/明胶(半)互穿网络((semi)IPNs)。通过材料万能测试仪、扫描电镜、吸水保水率测试详细研究了氧化海藻酸钠的氧化度、海藻酸钠与明胶不同质量比对(semi)IPNs的力学性能、吸湿性能的影响。研究结果表明,随着氧化海藻酸钠氧化度的增加,(semi)IPNs的力学性能、吸水保水性能呈现先增加后降低的趋势,氧化度为80%的氧化海藻酸钠交联制备的(semi)IPNs的性能达到最佳;并且海藻酸钠与明胶质量比为2∶1时所制备的(semi)IPNs的拉伸强度、断裂伸长率达到最大值,此时海藻酸钠与明胶的相容性得到了改善。氧化海藻酸钠交联体系的性能优于或等同于戊二醛交联体系,说明可以采用氧化海藻酸钠代替毒性较大的戊二醛交联蛋白质(如明胶)制备(semi)IPNs。     

辐射法制备PU／P（St—An）IPNs的微相分离及性能

首次采用Co~(60)-γ射线辐照法制备了聚氮酯/聚(苯乙烯-丙烯腈)互穿网络[PU/P(St-An)IPNs],并借助FTIR-PAS,SAXS及电子拉伸机等方法对材料的微相分离及力学性能进行了研究。研究表明,采用Co~(60)-γ辐照技术,可以有效地减小IPN体系的微相分离。丙烯腈含量增加,IPN体系的微相分离程度降低。当PU含量为40％时,IPN体系的微相分离程度最小,互穿程度最大。IPN材料的力学性能呈现出良好的协同效应。     

聚醚氨酯/环氧丙烯酸酯树脂同时互穿网络的研究

通过改变聚醚氨酯和环氧丙烯酸酯树脂组分比，合成了不同组成的同时互穿网络聚合物（SINs），采用红外光谱，扫描电镜和动态热力学分析等测试方法，研究了SINs材料的组分间分子混合和形态结构，探讨了材料的组分与力学及热学性能的关系。结果表明，互穿聚合物网络间存在微观相分离，两个聚合物网络间形成了部分的“网标交联”结构，SINs材料的力学和热学性能均有提高，当材料中聚醚氨酯和环氧丙烯酸酯树脂组分比为30／70（质量比）时，是综合力学性能和热学性能最好的塑料。     

聚合物梯度材料黏弹性断裂的双控制参数

针对组分材料体积分数任意分布的聚合物功能梯度材料,研究其在蠕变加载条件下Ⅰ型裂纹应力强度因子（SIFs）和应变能释放率的时间相依特征。由Mori-Tanaka方法预测等效松弛模量,在Laplace变换域中采用梯度有限元法和虚拟裂纹闭合方法计算断裂参数,由数值逆变换得到物理空间的对应量。分析边裂纹平行于梯度方向的聚合物功能梯度板条,分别考虑均匀拉伸和三点弯曲蠕变加载。结果表明,聚合物梯度材料应变能释放率随时间增加,其增大的程度与黏弹性组分材料体积分数正相关;材料的非均匀黏弹性性质产生应力重新分布,导致裂纹尖端应力场强度随时间变化,当裂纹位于黏弹性材料含量较低的一边时,应力强度因子随时间增加,反之,随时间减小。而且,材料的应力强度因子与时间相依的变化范围和体积分数分布以及加载方式有关,当体积分数接近线性分布时,变化最明显,三点弯曲比均匀拉伸的变化大。SIFs随时间的延长增加或减小、加剧或减轻裂纹尖端部位的“衰坏”,表明黏弹性功能梯度裂纹体的延迟失稳需要联合采用应力强度因子与应变能释放率作为双控制参数。     

高阻尼互穿聚合物网络的分子设计

从互穿聚合物网络(IPN)分子设计对阻尼性能影响的角度综述了近年来国内外主要的研究成果,内容涉及阻尼性能的评价,分子设计的理论依据,IPN组分的选择,分子主链的设计和侧链的引入,IPN组成的配比优化,以及合成条件的影响等方面,并展望了未来高阻尼IPN分子设计研究的前景.     

不饱和聚酯／聚氨酯互穿网络聚合物基玻璃纤维增强 …

研究了以不饱和聚酯／聚氨酯互穿网络聚合物为基的玻璃纤维复合材料的动态热机械性能及应用性能。结果表明,在不饱和聚酯树脂中加入５％－１０％的聚氨酯,使基质形成互秀利于提高由此得到的复合材料的性能。     

Preparation, Morphology and Damping Property of PU/UP Interpenetrating Polymer Networks

Interpenetrating polymer networks (IPNs) composed of acrylate-modified polyurethane (PU)/unsaturated polyester (UP) resin via simultaneous polymerization with various component ratios of PU/UP were prepared. The polymerization processes of IPNs were traced through infrared spectrum (IR) techniques, by which the phase separation in systems could be controlled effectively. Results for the morphology and miscibility among multiple phases of IPNs, obtained by transmission electron microscope (TEM) indicated that the domains between two phases were constricted in nanometer scales. The dynamic mechanical thermal analyzer (DMTA) detection results revealed that the loss factor (tanδ) and loss modulus (E") increased with the polyurethane amounts in system, and the peak value in curves of tanδand E" appeared toward low temperature ranges. Maximum tanδvalues of all samples were above 0.3 in the nearly 50℃ranges. Also, the mechanical properties of PU/UP IPNs were studied in detail.     

Polymerization Process and Morphology of Polyurethane/Vinyl Ester Resin Interpenetrating Polymer Networks

A series of polyurethane （PU）/vinyl ester resin （VER） simultaneous IPNs （interpenetrating polymer networks） with different component ratios and comonomers types introduced to VER were synthesized and the polymerization processes were traced by Fourier transform infrared spectroscopy （FTIR） to study the kinetics of IPNs and hydrogen bonding action within multi-component. Furthermore, the relationship of polymerization process with morphology was investigated in detail for the first time by the morphological information given by chemical action between two networks besides physical entanglement, atomic force microscope （AFM） observation and dynamic mechanical analysis （DMA）. The results indicated that the degree of hydrogen bonding （Xb,UT,%）, calculated from functional group conversional rate and fine structures gained from FT-IR spectra of two networks, were affected by PU/VER weight ratios and comonomer types of VER. The relationship of formation kinetics and morphology showed that the change of Xb,UT （%） values exhibited excellent consistency with that of phase sizes observed by AFM and detected by DMA.     

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。     

梯度钛合金裂纹扩展速率测试及梯度对扩展寿命影响

为明确梯度材料中裂纹扩展速率分布情况,对含裂纹TC11-TC4以及TA15-TA2两种组合梯度钛合金进行标准三点弯疲劳试验。试验结果表明:梯度结构中不同部位的相同组分扩展性能相同,给出了4种3D打印组分钛合金的Paris公式;梯度材料组分弹性模量的变化会改变裂纹尖端应力强度因子,对位于模量较低一侧的裂纹扩展有抑制作用;过渡层影响厚度范围内裂纹扩展速率介于两种组分之间且连续过渡,表明梯度材料可以消除异种材料连接的界面效应,提出基于组分材料体积分量的混合率描述梯度层中扩展性能的分布规律;恒定载荷试验中仅扩展方向不同情况下寿命有显著差别,验证了合理安排梯度参数可提高结构出现裂纹后的生存能力,其中扩展性能以及模量的变化分布对扩展寿命均有影响。     

国产CCF300碳纤维单向织物液体成型工艺性及其复合材料力学性能

选取国产碳纤维CCF300所制备的2种单向织物,单向无纬织物U3160及单向无屈曲织物KUC160,分别对其预成型体进行压缩特性和渗透特性测试,以研究2种单向织物的液体成型工艺性,并采用树脂传递模塑(RTM)工艺制备2种单向织物/双马来酰亚胺树脂基复合材料,测试并对比其面内力学性能。结果表明:预成型体压缩试验中,嵌套效应受压力及织物层数影响较大,压力越高、层数越多,嵌套效应越显著。U3160织物的嵌套效应较KUC160织物更为明显,在较高压力下,KUC160织物预成型体的纤维体积分数较U3160织物的下降了约20%。渗透率测试结果表明:相比U3160织物,KUC160织物0°方向的渗透率较高,而90°方向的渗透率有所降低;这是由于经编线的绑缚作用能促进0°方向的宏观流动,而阻碍90°方向的微观渗透。此外,KUC160织物的经编线与U3160织物的纬向纱线的导流作用也对渗透率有影响。力学性能试验结果表明:相比U3160织物增强复合材料,KUC160织物增强复合材料0°方向的拉伸、弯曲和压缩性能均有所下降,拉伸强度和弯曲模量降幅最大,分别约为11%和21%;而层间剪切强度有小幅提高,增幅约为8%。      

Design analysis of three-layered structural composites based on post-consumer recycled plastics and wood residues

Three-layered structural composites were produced from municipal plastic wastes and wood flour residues to investigate the effects of design parameters on their flexural and impact performance. The studied parameters include wood content, thickness of individual composite layers, as well as stacking sequence and configuration (symmetric and asymmetric structures). The results indicate that the core layer has a lower influence on the flexural properties of structural beams in comparison with the skins. But depending on beam configuration (stacking sequence), different flexural characteristics can be obtained using the same composite layers. The classical beam theory was used to predict the flexural modulus with high precision. In addition, performance of the beams under impact tests was shown to be independent from their stacking sequences and layer thicknesses for each configuration.     

Performance of functionally graded sandwich composite beams under shock wave loading

The dynamic behavior of sandwich composites made of E-Glass Vinyl-Ester (EVE) facesheets and graded Corecell™ A-series foam was studied using a shock tube apparatus. The foam core was monotonically graded based on increasing acoustic wave impedance, with the foam core layer of lowest wave impedance facing the blast. The specimen dimensions were held constant for all core configurations, while the number of core layers varied, resulting in specimens with one layer, two layer, three layer, and four layers of foam core gradation. Prior to shock tube testing, the quasi-static and dynamic constitutive behavior (compressive) of each type of foam was evaluated. During the shock tube testing, high-speed photography coupled with the optical technique of Digital Image Correlation (DIC) was utilized to capture the real-time deformation process as well as mechanisms of failure. Post-mortem analysis was also carried out to evaluate the overall blast performance of these configurations. The results indicated that increasing the number of monotonically graded foam core layers, thus reducing the acoustic wave impedance mismatch between successive layers, helped maintain structural integrity and increased the blast performance of the sandwich composite.     

基于热应力分析的固体氧化物燃料电池阳极功能层优化设计

为了降低固体氧化物燃料电池在制备和工作过程中产生的热应力, 提高电池的电化学性能, 在电池中引入功能梯度层可以有效减小电池各层之间材料参数的差异, 从而缓解各层之间的热失配应力。本研究将阳极功能层引入燃料电池中, 通过阳极功能层子层数目和非线性梯度成分指数n控制各子层材料属性的变化情况, 研究了燃料电池在800℃下的热应力分布。结果表明: 选取适当的指数n和阳极功能层的分层数目可以明显降低阳极层的最大拉应力和电解质层的最大压应力。