利用带孔试样的拉伸试验推测共混物的增强机理

用自行设计的带孔试样进行拉伸试验以模拟聚丙烯(PP)共混物试样受力时的变化。利用带孔试样拉伸试验得到的启示,系统分析了PP／CaCO3拉伸屈服强度的变化机理,发现塑性变形约束机制和微区硬化机制是极低分散相浓度共混物拉伸屈服强度高于纯PP拉伸屈服强度的原因,应力集中发生叠加后屈服易在整个基体层内扩散是高分散相浓度共混物拉伸屈服强度降低的原因。并成功地解释了多种体系中存在的这类现象。     

剪切作用下POE-g-MAH和PP-g-MAH对PA1010/PP共混物的增容作用

采用熔融共混的方法制备了聚酰胺1010/聚丙烯（PA1010/PP）共混物,通过扫描电镜、力学性能和差示扫描量热等方法研究了剪切作用下马来酸酐接枝乙烯-辛烯共聚物（POE-g-MAH）和马来酸酐接枝聚丙烯（PP-g-MAH）对PA1010/PP共混物的增容作用。结果表明,同样条件下,PP-g-MAH增容体系的相区尺寸较小,相界面更模糊,PP相的结晶温度和结晶度明显提高,共混物的拉伸强度和冲击强度均高于非增容体系。而POE-g-MAH增容体系的相区尺寸相对较大,PP相的结晶温度和结晶度明显降低,共混物只有冲击强度明显高于非增容体系,拉伸强度略低于非增容体系。     

尼龙66/聚酚氧共混体系的共混形态和力学性能

采用扫描电镜、动态力学分析仪和材料试验机研究了尼龙66(PA66)与聚酚氧(PHE)共混体系的共混形态和力学性能。研究表明:氢键作用使得二者熔融共混后形成部分相容的两相聚集态结构;以PA66为主体时,PHE以颗粒形态分散在PA66基体中,随PHE含量增加,分散相颗粒尺寸下降;此时尼龙相的玻璃化转变温度(Tg)增大,PHE相的Tg提高,共混体系拉伸强度增加,冲击强度下降。PA66/PHE质量比达到40/60后发生相反转,PA66分散相颗粒尺寸明显小于PHE为分散时相的颗粒尺寸。PHE相的Tg随PA66含量增加而增大,随PA66含量增加,共混体系拉伸强度和冲击强度均增大。     

PA11/PA1010共混物的性能研究

采用熔体共混的方法制备了聚酰胺11/聚酰胺1010(PA11/PA1010)共混物,通过力学性能和差示扫描量热(DSC)测试,研究了PA11/PA1010共混物的力学与结晶性能。测试结果表明:PA1010对PA11同时具有增韧、增强作用;当PA11/PA1010为70/30时,共混物开始出现两个结晶峰和低温熔融峰;共混物的结晶和熔融以PA11为主,兼具有PA11和PA1010的优良性能;断裂伸长率、拉伸强度与缺口冲击强度均达到极大值。     

PLA/PCL共混物的制备及性能分析

采用熔融共混法制备了聚乳酸(PLA)/聚己内酯(PCL)共混物,探讨了PCL含量对共混物加工性能和力学性能的影响。结果表明,随着PCL含量的增加,共混物拉伸强度逐渐降低,断裂伸长率逐渐减小;冲击强度则先增加后减小,当PCL质量分数为15%时,达到最大。随后探讨了柠檬酸三丁酯(TBC)、聚乙二醇(PEG) 2种相容剂对聚乳酸/聚己内酯共混物的力学性能、热性能和断面微观结构形态的影响。结果表明,加入适量的增容剂可以增强两相界面的粘接力,改善共混物的力学性能;共混物的Tg和Tc均降低,说明PLA与PCL的相容性得到改善;共混物断面的SEM表明,分散相的粒径变小,两相之间呈现良好的的相容性。     

PVC／ABS共混物性能与配比的优化选择

本文讨论了廉价均聚物PVC与ABS三元共聚物共混体的开发及两种共混组分性能之间的内在关系.组分的相结构强烈地影响着共混物的性能.PVC/ABS共混物呈微观多相:即硬质的连续相和软质的分散相,它们之间是部分相容的.从这种部分相容的共聚物中,可观察到这两种组分在拉伸强度和模量、挠曲强度和模量以及粘度方面的协同效应.两组分间的相互作用可用来解释上述性能的实验结果较PVC和ABS相应各自经验数据的加和值表现出正偏差的原因.这种共混性能补偿无疑是分散相存在的结果.PVC/ABS共混材料令人感兴趣的地方不仅     

PA6/PMMA共混物的增容研究

采用三种不同组成的甲基丙烯酸甲酯(MMA)与甲基丙烯酸缩水甘油酯(GMA)共聚物P(MMA-co-GMA)作为增容剂,研究了三种增容剂用量和组成对尼龙6 (PA6)/聚甲基丙烯酸甲酯(PMMA)(70/30)共混物性能和微观形貌的影响。结果表明,三种增容剂均能使PMMA的玻璃化转变温度逐渐向低温处移动,缩小两相玻璃化转变温度之间的差值,减小分散相的粒径尺寸,改善PA6/PMMA两相之间的相容性。三种不同组分的P(MMA-co-GMA)增容剂,均能提高PA6/PMMA (70/30)共混物的加工黏度、拉伸强度、弹性模量及弯曲强度;增容剂的用量和组成对共混物的冲击强度有影响,优化用量和组成,可以提高冲击强度。     

尼龙6/聚碳酸酯共混物的增容研究

通过乳液聚合合成组成不同的甲基丙烯酸甲酯与马来酸酐共聚物,应用到尼龙6(PA6)/聚碳酸酯(PC)(75/25)共混物中,考察了共聚物用量及组成对共混物性能的影响。结果表明,马来酸酐含量为15%及20%的共聚物可有效提升PA6/PC共混物的冲击强度、拉伸强度及弯曲强度;随着共聚物用量的增加,共混物的拉伸强度与弯曲强度得到显著提升;甲基丙烯酸甲酯与马来酸酐共聚物可缩小共混物两相的玻璃化转变温度的差值,减小分散相的尺寸。实验结果表明,甲基丙烯酸甲酯与马来酸酐共聚物能有效提升PA6/PC共混物基体间的相容性。     

有机蒙脱土对PLA/PBS共混物相结构及性能的影响

通过熔融共混的方法制备了聚乳酸/聚丁二酸丁二醇酯/有机蒙脱土(PLA/PBS/OMMT)复合材料,研究了OMMT对不同组成的PLA/PBS共混物微观结构的影响,进而研究其对热性能、热稳定性以及拉伸性能的影响。微观结构结果表明,添加OMMT到PLA/PBS共混物中,能够降低分散相的尺寸,均化分散相尺寸分布,使PLA/PBS(50/50)共混物的双连续相结构改变为海-岛结构。DSC结果表明,PBS能够提高PLA的结晶能力,添加OMMT后,PLA相的冷结晶温度和熔点明显提高,结晶度达到39.5%,PLA的结晶形貌更加完善。TG结果表明,PBS能够提高PLA/PBS共混物热稳定性,添加OMMT后,进一步提高了共混物的热稳定性,起始分解温度提高至307.3℃。添加OMMT后,PLA/PBS/OMMT复合材料的拉伸性能得到提高,PLA/PBS/OMMT(80/20/1)复合材料的拉伸强度和断裂伸长率分别达到53.9 MPa和34.2%,在保证材料强度的前提下,得到了较好的延展性。     

基体性质对聚丙烯力学性能的影响

采用过氧化二异丙苯(DCP)作为降解剂,以聚丙烯(PP)为基体,以三元乙丙橡胶(EPDM)为增韧剂,研究了EPDM对降解PP/EPDM共混物力学性能的影响,并利用扫描电子显微镜(SEM)对共混体系微观形貌进行了表征。熔体质量流动速率结果表明:随着EPDM质量分数从10%增加到30%时,对应共混物的熔体质量流动速率明显下降,从14.8 g/10 min下降到10.8 g/10 min。随着EPDM用量的增加,共混物的冲击强度明显增大,从30.06J/m增长到90.26 J/m,拉伸强度有所减小。SEM照片显示,随着EPDM用量的增加,共混物中分散相的尺寸明显增大。因为EPDM含量的增加,导致分散的橡胶粒子产生"聚并",从而分散相的相区尺寸增大。     

Structural characterization of semicrystalline polymer blends by small-angle neutron scattering

A series of phase-separated polyethylene-polypropylene blends, which have undergone different thermal treatments, have been analysed by small-angle neutron scattering (SANS). The coherent scattering from normal hydrogenated blends is virtually zero, but strong contrast may be induced by partial or complete deuteration (labelling) of either phase. Here, the scattering from blends with complete labelling of the polyethylene phase was analysed to provide the domain dimensions by means of a theory due to Debye using an exponential correlation function. By this means the mean chord intercept lengths of both phases were shown to be in the range 1000–10000Å. The scattering from blends with partial labelling of the polyethylene was analysed to give the radius of gyration of the molecules in the polyethylene domains, which was found to be close to that measured in the homopolymer. For melt-quenched blends the deuterated polyethylene was shown to be statistically distributed in the polyethylene phase, whereas for slow-cooled blends, partial segregation of the labelled molecules occurred.     

The phase inversion and morphology of nylon 1010/polypropylene blends

Noncompatibilized and compatibilized blends of nylon 1010/PP blends having five different viscosity ratios were prepared by melt extrusion. Glycidyl methacrylate-grafted-polypro-pylene (PP-g-GMA) was used as the compatibilizer to enbance the adhesion between the two polymers and to stabilize the blend morphology. The effect of the viscosity ratio on the morphology of nylon 1010/polypropylene blends was investigated, with primary attention to the phase-inversion behavior and the average particle size of the dispersed phase. The relationship between the mechanical properties and the phase-inversion composition was investigated as well. Investigation of the morphology of the blends by microscopy indicated that the smaller the viscosity ratio (ηpp/ηpa) the smaller was the polypropylene concentration at which the phase inversion took place and polypropylene became the continuous phase. The compatibilizer induced a sharp reduction of particle size, but did not have a major effect on the phase-inversion point. An improvement in the mechanical properties was found when nylon 1010 provided the matrix phase. © 1996 John Wiley & Sons, Inc.     

Blends of polypropylene with poly(cis‐butadiene) rubber. III. Study on the phase structure and morphology of incompatible blends of polypropylene with poly(cis‐butadiene) rubber

Scanning electron microscopy (SEM) was used to study the structure and morphology of partly compatible binary blends of polypropylene with poly(cis‐butadiene) rubber. The SEM images were transformed by digital image process software designed by our group, and binarized images were obtained. The size (mean diameters d_p and characteristic lengths L) of phases was calculated using binarized images. Small‐angle light scattering was employed to study the structure and morphology of phases in the blends. The structural parameters, including correlation distance a_c, average chord lengths l , and mean diameter D_S to describe the structure and morphology of phases in binary blends, were calculated based on the corresponding theory. The variation of correlation distance a_c, average chord length l , and mean diameter D_S were the same as that of mean diameters d_p and characteristic length L. At the same time, the distribution of sizes of the dispersed phase in binary blends was calculated with graph transition technique, which possessed log‐normal distribution characterization. The power spectrum images corresponding to small‐angle light scattering images were obtained by two‐dimensional fourier transformation of binary images. The correlation distances a_cf and average chord length l _f have been calculated by intensity of power spectrum images and that was the same as a_c and l . © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4900–4909, 2006     

Rayleigh散射研究非相容聚苯乙烯／顺丁橡胶合金相结构

用光散射在线采集与分析方法完成了熔融混炼过程中非相容高分子共混物的形态结构分析。选择了聚苯乙烯／顺丁橡胶合金体系。使用了小角前向光散射和小角背散射（在线）技术，用Debye-Bueche光散射理论的结构参数如相关蹁ac、平均弦长l、平均旋转半径Rg和积分不变量Q表征了共混物中分散相尺度和均匀性。用扫描电子显微镜（SEM）测定了共混物中分散相尺寸，并与光散射的结果进行了比较。ac,l和Rg的变化规律与显微镜的结果是一致的。用积分不变量Q研究了共混物的均匀性。     

相容剂和加工工艺对PA1010/PP共混体系形态和力学性能的影响

以马来酸酐（MAH）和苯乙烯（St）多单体熔融接枝聚丙烯[PP-g-(MAH-co-St）]为相容剂,制备了聚酰胺10101/聚丙烯（PA1010/PP）共混体系。用毛细管流变仪、扫描电子显微镜、力学性能测试等方法研究了和加工工艺相容剂对PA1010/PP共混体系的形态和力学性能的影响。结果表明,相容剂PP-g-(MAH-co-St)有效降低了PA1010/PP共混体系的熔体流动速率;该共混体系熔体属于假塑性流体,熔体黏度随PP-g-(MAH-co-St)含量的增加逐渐增大;随着相容剂含量的增加,PA1010/PP共混体系中分散相PP的粒径逐步减小,力学性能得到改善,PA1010/PP/PP-g-(MAH-co-St)为70/25/5和70/20/10的共混体系的拉伸强度分别比PA1010/PP (70/30)共混体系提高了55.0 %和61.9 %,冲击强度分别提高了61.0 %和129.7 %;剪切速率为706.5 s-1时出现熔体破裂现象,剪切速率为5002.65 s-1时出现严重熔体破裂。     

Rayleigh散射研究部分相容聚苯乙烯／顺丁橡胶合金相结构

用光散射在线采集与分析方法完成了熔融混炼过程中非相容高分子共混物的形态结构分析。选择了聚苯乙烯／顺丁橡胶合金体系；使用了小角前向光散射和小角背散射(在线)技术，用Debye-Bueche光散射理论的结构参数如相关距离ac、平均弦长l、旋转半径Rg和积分不变量Q表征了共混物中分散相尺度和均匀性，讨论了合金体系的相容性。用扫描电子显微镜测定了共混物中分散相尺寸，并与光散射的结果进行了比较。ac、l和Rg的变化规律与显微镜的结果是一致的。用积分不变量Q研究了共混物的均匀性。     

尼龙1010／马来酸酐接枝聚乙烯共混体系结晶行为和力学性能的研究

将尼龙1010与马来酸酐接枝聚乙烯进行熔融共混,使用DSC、扫描电镜等方法研究了共混物的结晶行为、共混物形态以及力学性能。结果表明:接枝聚乙烯通过与尼龙1010在熔融共混时生成的接枝共聚物改善了共混组份两相之间的相容性和共混形态;共混物中尼龙组份的结晶熔融热焓下降;共混物在保持较高刚性的同时其干态及低温冲击性能较纯尼龙1010有明显提高。     

聚丙烯的官能化及与尼龙1010相容性研究

对聚丙烯(PP)进行官能化,并研究了接枝单体含量、引发剂含量对接枝率和熔体流动速率的影响,再将不同接枝率的PP与尼龙1010共混,研究了接枝率对共混物机械性能及相容性的影响;用扫描电子显微镜观察共混物的形态,与未增容共混体系相比,增容后共混体系分散相尺寸明显变小。     

MORPHOLOGY,CRYSTALLIZATION BEHAVIORS,AND MECHANICAL PROPERTIES OF PA1010/HIPS AND PA1010/HIPS-g-MA BLENDS

The binary blends of polyamide 1010 (PA1010) with the high-impact polystyrene (HIPS)/maleic anhydride (MA) graft copolymer (HIPS-g-MA) and with HIPS were prepared using a wide composition range. Different blend morphologies were observed by scanning electron microscopy according to the nature and content of PA1010 used. Compared with the PA1010/HIPS binary blends, the domain sizes of dispersed-phase particles in PA1010/HIPS-g-MA blends were much smaller than that in PA1010/HIPS blends at the same compositions. It was found that the tensile properties of PA1010/HIPS-g-MA blends were obviously better than that of PA1010/HIPS blends. Wide-angle x-ray diffraction analyses were performed to confirm that the number of hydrogen bonds in the PA1010 phase decreased in the blends of PA1010/HIPS-g-MA. These behaviors could be attributed to the chemical interactions between the two components and good dispersion in PA1010/HIPS-g-MA blends.