尼龙6/氯化钾复合材料的结晶与性能

通过熔融共混法制备了不同KCl含量下的尼龙6(PA6)/KCl复合材料,采用示差扫描量热仪(DSC)、流变仪、红外光谱(IR)、电子拉伸机等研究了KCl含量对PA6/KCl复合材料结晶行为、流变性能及力学性能的影响,并研究了其受限机制.力学性能研究结果表明,随着KCl含量的增加,PA6/KCl复合材料拉伸强度和冲击强度呈现出先增大后减小的趋势,在KCl含量为3 phr时,复合材料拉伸强度和冲击强度分别达到最大值82.67 MPa和7.34 k J/m~2,较纯PA6分别增加了10.8%和34.68%,动态力学性能测量结果表明,在测量温度范围内,复合材料的储能模量均高于纯PA6,在25℃体系储能模量(G')随KCl含量的增加而增大,复合体系抵抗弯曲变形能力增加,而结晶行为研究结果表明,增加KCl的含量,PA6/KCl复合材料的成核温度、晶体生长温度、熔融温度及玻璃化转变温度均向低温方向移动,成核密度和成核速率也逐渐减小,结晶能力下降,结晶度减小,结晶度由原来25.30%变为19.34%,而结晶诱导时间逐渐增加.流变性能研究结果表明,随着KCl含量的增加,复合体系的零剪切黏度逐渐增加,且所有的体系均呈现出假塑性流体行为,剪切变稀现象越来越明显,特征松弛时间τ_1、τ_2和τ_3逐渐增加,复合体系的松弛机制发生变化.     

离子液体增塑改性玉米淀粉/聚丁二酸丁二醇酯共混材料的结构与性能

为考察离子液体对淀粉/聚丁二酸丁二醇酯(PBS)的作用效果,降低淀粉/PBS的脆性,以离子液体(1-丁基-3-甲基咪唑氯盐[BMIM]Cl)作为增塑改性剂通过熔融共混法制备了玉米淀粉/聚丁二酸丁二醇酯(PBS)共混材料,采用红外光谱(FTIR)、扫描电镜(SEM)、热重分析(TGA)、X射线衍射分析(XRD)及力学性能测试方法研究了[BMIM]Cl对淀粉/PBS共混材料结构和性能的影响.结果表明,[BMIM]Cl能与淀粉/PBS分子发生强相互作用,破坏淀粉/PBS共混物中原有的氢键与结晶结构,增强界面相互作用,改善相容性,进而改变淀粉/PBS共混材料的结构与性能;[BMIM]Cl的加入不影响淀粉/PBS的热稳定性,可使材料玻璃化转变温度(Tg)、结晶温度(Tc)、冷结晶温度(Tcc)及结晶度(Xc)降低.[BMIM]Cl具有显著降低淀粉/PBS脆性的作用,使其断裂伸长率大幅度增加,拉伸强度和弹性模量降低.     

复合型季铵化聚醚砜碱性聚合物电解质膜的制备及性能

利用4,4?-二氟二苯砜(DFDPS)、9,9?-双(4-羟苯基)芴(BHPF)、2,2?-二(4-羟基苯基)丙烷(双酚A)及4,4?-(六氟异丙叉)双酚(双酚AF)为原料,制备了2类具有不同主链刚性的聚醚砜材料.以聚醚砜及其氯甲基化产物按一定质量比采用溶液浇铸法,制备了2类新型共混阴离子交换膜,并避免了成膜过程中的相分离现象.在高分子主链上通过引入双酚芴(BQPAES系列)及双酚A(BQPES系列)结构调整主链的刚性,探讨了主链刚性对性能的影响;表征了共混膜的离子交换容量(IEC)、吸水及溶胀特性与离子电导率,并考察了它们的耐水解和耐碱稳定性.结果表明:2种聚合物相容性良好,共混膜质地均一,柔韧透明,吸水率和溶胀率适中,均随着温度的升高逐渐增加、随着聚醚砜含量增加逐渐减小;在90?C时,离子电导率最高达到89 m S/cm.经过沸水处理24 h后,均保持高机械强度,失重率低于5%;经2 mol/L的Na OH溶液30?C处理168~240 h后离子电导率仍可保持65%~80%.由于含双酚芴结构的高分子主链具有更高的刚性,在类似IEC条件下,BQPAES膜显示了比BQPES膜更好的尺寸稳定性和化学稳定性,同时维持了较高的电导率水平.由此表明,复合处理及适度提高高分子主链的刚性,有利于提高膜的性能.     

聚对苯二甲酸丁二醇酯/聚(对苯二甲酸丁二醇酯-e-己内酯)二元结晶共混体系的相容性和结晶行为

聚对苯二甲酸丁二醇酯(PBT)/聚(对苯二甲酸丁二醇酯-e-己内酯)(PBT-PCl)是一个新制备的具有分子间排斥相互作用的A/AxB1?x型两元结晶共混体系. 根据两元平均场模型,报道对苯二甲酸丁二醇酯(BT)与"-己内酯(CL)结构单元的相互作用参数为0.305. DSC研究发现,此共混物呈现了与典型的共聚物/均聚物共混物不同的结晶特征. PBT-PCL影响PBT链的活动力和晶片堆积;同时PBT-PCL的结晶受到先期结晶的PBT晶粒的阻滞. 尽管拥有相同的BT单元,共混的两组分在组成变化范围内仍没有形     

Properties of immiscible and ethylene-butyl acrylate-glycidyl methacrylate terpolymer compatibilized poly (lactic acid) and polypropylene blends

Poly(lactic acid) (PLA) and polypropylene (PP) blends of various proportions were prepared by melt-compounding. The miscibility, phase morphology, thermal behavior, and mechanical and rheological properties of the blends were investigated. The blends were immiscible systems with two typical morphologies, spherical droplet and co-continuous, and could be obtained at various compositions. Complex viscosity, storage modulus and loss modulus depend on the PP content. Thermal degradation of all blends led to two weight losses, for PLA and PP. The incorporation of PP improved the thermal stability of the blend. The effect of compatibilizer (ethylene-butyl acrylate-glycidyl methacrylate terpolymer, EBA-GMA) on the morphology and mechanical properties of 70/30 w/w PLA/PP blends was investigated. The tensile strength of these blends reached a maximum for 2.5 wt% EBA-GMA, and impact strength increased with increasing EBA-GMA content, suggesting that EBA-GMA is an effective compatibilizer for PLA/PP blends.     

Characterization of the effect of REC on the compatibility of PHBH and PLA

This study reports the compatibility of the biobased polymers poly(3-hydroxybutyrate-co-3- -hydroxyhexanoate) (PHBH) and poly(lactic acid) (PLA), as well as the effect of the addition of a reactive epoxy compatibilizer (REC) to the PHBH/PLA blend. The chemical structure, thermal performance, surface morphology and mechanical properties of the blends were measured using fourier transform infrared spectroscopy, differential scanning calorimetry, dynamic thermo-mechanical analysis, thermogravimetric analysis, scanning electron microscopy, and impact and tensile testing.PHBH and PLA were partially compatible, and a PHBH/PLA mass ratio of 80:20 was selected for evaluation with an REC. The REC decreased the difference between the glass-transition temperatures of PHBH and PLA, decreased the particle size of the dispersed phase of the PHBH/PLA blend and produced uniform particle distribution. Moreover, the REC improved the elongation at break and impact strength of the PHBH/PLA blend. These results show that the addition of an REC improves the compatibility of PHBH and PLA.     

Structure-properties correlations in poly(ε-caprolactone)/poly(styrene-co-acrylonitrile)/nanosilica mixtures: Interrelationship among phase behavior,morphology and non-isothermal crystallization kinetics

In this work, the effects of amorphous poly(styrene-co-acrylonitrile) (SAN) chains and hydrophilic and hydrophobic nanosilica at different loadings on the non-isothermal crystallization kinetics of PCL phase have been evaluated using different theoretical models including Avrami, modified Avrami, Ozawa and Mo equations. Using microscopic observations, the interrelations among the changes in the kinetics parameters and the morphology and phase behavior of PCL/SAN and PCL/SAN/nanosilica mixtures have been thoroughly investigated. Microscopic observations on the nanocomposites showed differences in the nanofiller dispersion and distribution state as well as preferential migration and localization state. These differences lead to contradictory trends in the effects of hydrophilic and hydrophobic nanosilica on the crystallization kinetics of pure PCL and PCL/SAN blends. The nanoparticle migration during non-isothermal DSC tests in PCL/SAN blends, the formation of nanoparticle agglomerates at higher loadings, the restrictions imposed on the molecular movements in the crystallization growth stage and slower phase separation and dissolution of PCL/SAN/silica mixtures result in the cooling rate dependence of the kinetics parameters.     

给受体共混质量比对P3HT:PCBM薄膜结构和器件性能的影响

以聚3-己基噻吩(P3HT)为给体、[6,6]-苯基-C61-丁酸甲酯(PCBM)为受体的光伏体系作为研究对象,采用溶剂退火的后处理方法制备薄膜样品,利用紫外-可见(UV-Vis)吸收光谱、原子力显微镜(AFM)、X射线衍射(XRD)等测试手段分别对共混膜样品的形貌和结构进行表征,同时利用熵值统计方法对AFM形貌图像进行分析处理.并在此基础上制备太阳能电池器件,其结构为氧化铟锡导电玻璃/聚3,4-乙撑二氧噻吩:聚苯乙烯磺酸盐/聚3-己基噻吩:[6,6]-苯基-C61-丁酸甲酯/金属铝(ITO/PEDOT:PSS/P3HT:PCBM/Al),研究了给受体共混比例(质量比)对活性层薄膜以及电池性能的影响.结果表明,受体PCBM含量的增加会影响P3HT给体相的有序结晶,当给受体比例为1:1时,活性层薄膜具有较宽的紫外-可见吸收特征,且具有较好的相分离和结晶度,基于该样品制备的电池器件其光电转换效率达到三种比例的最大值(2.77%).表明退火条件下,改变给受体比例可以影响活性层的微纳米结构而最终影响电池的光电转换效率.     

Morphology and properties of nanostructured materials based on polypropylene/poly(butylene succinate) blend and organoclay

Nanostructured materials based on organically modified montmorillonite (OMMT) and polypropylene (PP)/poly(butylene succinate) (PBS) blend were prepared via melt-mixing of PP, PBS, and OMMT in a batch mixer. The weight ratio of PP and PBS was 70:30, and the OMMT loading varied from 0.5 to 5 wt%. The surface morphologies of unmodified and OMMT-modified blend were studied by field-emission scanning electron microscopy. Results showed that the particle size of the dispersed PBS phase was significantly reduced with the addition of a small amount of OMMT (1.5 wt%). Upon the addition of 5 wt% of OMMT, the domain size of the dispersed PBS phase changed significantly from the unmodified blend, and a homogeneous dispersion of very fine particles of PBS was observed. The degree of dispersion of silicate layers in the blend matrix was characterized by X-ray diffraction and transmission electron microscopy. The improved adhesion between the phases and the fine morphology of the dispersed phase contributed to the significant improvement in the properties and thermal stability of the final nanocomposite materials. On the basis of these results, we describe a general understanding of how the morphology is related to the final properties of OMMT-incorporated PP/PBS blend.     

聚苯胺改性技术的研究新进展

导电聚合物由于有很大的应用前景而引起了很多研究者的兴趣。在导电聚合物中,聚苯胺由于具有很高的导电性、热稳定性、容易制备等性质而受到了格外的关注。但是聚苯胺同样有缺点,例如应用范围狭小、很难进行加工等。为了提高聚苯胺的加工性能,乳液聚合是一种有效的改性方法。本文讨论了用乳液聚合或反相乳液聚合合成聚苯胺以及聚苯胺的共聚物,同时也报道了聚苯胺与其它物质复合共混和掺杂的研究结果,并且研究了它们的结构以及各方面的性能。通过改性,可使得聚苯胺的加工性得到很好的改善。