HDPE/sPS/SEBS共混物中增容剂的分布及对力学性能的影响

用2种组成相近而相对分子质量不同的苯乙烯-乙烯/丁烯-苯乙烯共聚物(SEBS)增容高密度聚乙烯/间规聚苯乙烯(m(HDPE)/m(sPS)=80/20)共混物。利用增容剂(SEBS)与共混物组分之间溶解性的差异,以四氢呋喃(THF)为溶剂选择刻蚀掉增容剂相,采用扫描电镜(SEM)观察了共混物的形态结构及增容剂在共混物中的分布情况;结合拉伸测试,阐明了增容剂的相对分子质量及其分布对HDPE/sPS共混物力学性能的影响。结果表明,较低相对分子质量的SEBS主要分布在两相界面,并能显著提高两相界面粘接性,进而能有效提高共混物的拉伸强度;而较高相对分子质量的SEBS更倾向以胶束形式分散在HDPE基相中,不能明显改善界面强度,但却有利于改善共混物的韧性。     

SG增容PA6/sPS共混体系的形态结构与力学性能

采用一系列不同甲基丙烯酸环氧丙酯(GMA)含量的苯乙烯-甲基丙烯酸环氧丙酯共聚物(SG)增容尼龙6(PA6)/间规聚苯乙烯(sPS)(80/20)共混物,通过扫描电镜及拉伸实验考察了SG共聚物中GMA的含量对共混物形态结构及力学性能的影响。形态观察显示,SG共聚物可以有效地降低PA6/sPS共混物中分散相的尺寸,增加两相界面间的粘接力;SG共聚物中GMA的含量对其增容效果有较大影响,质量分数为5%左右时,SG共聚物对PA6/sPS共混物的增容效果最佳。拉伸实验结果表明,PA6/sPS共混物的拉伸强度及模量随着SG共聚物的加入而增加,但其断裂伸长率在较高SG含量时则有所下降。     

sPS与iPP共混体系的力学性能、热性能及形态结构

采用SEM研究了B30/iPP,B30/sPS和sPS/iPP/B30共混体系的相形态结构。结果表明,B30/iPP,B30/sPS可相容;sPS/iPP是不相容体系,但B30可作为sPS/iPP共混体系的相容剂。DSC结果表明,加入适量的相容剂B30,共混体系中iPP玻璃化温度(iPP-Tg)随B30加入量增加而逐渐升高,而sPS玻璃化温度(sPS-Tg)随B30加入量增加而逐渐降低。在最佳配比条件下,共混物的力学性能比均聚物的要好.共混体系sPS/iPP/B30=90/10/10的无缺口冲击强度为42.3 kJ/m2,拉伸强度为33.7 MPa。     

胺基化反应增容PC/ABS共混物

采用熔融共混方法制备了ABS树脂接枝马来酸酐接枝共聚物(ABS-g-MAH),将接枝共聚物与1-(2氨乙基)哌嗪反应制备了增容剂,通过红外光谱表征确定了预期反应的发生.将增容剂部分替代聚碳酸酯(PC)/ABS共混物中的ABS树脂,考察了增容剂对PC/ABS共混物的力学性能的影响.结果表明,加入增容剂后,PC/ABS共混...     

熔融挤出HDPE/EVOH共混物的微观结构及性能

采用高密度聚乙烯(HDPE)接枝马来酸酐(MAH)或甲基丙烯酸缩水甘油酯(GMA)作为增容剂,熔融挤出制备HDPE/乙烯-乙烯醇共聚物(EVOH)共混物.通过扫描电镜观察、气体渗透试验以及力学性能试验,分析增容剂对共混物相容性的影响,并研究共混物的力学性能和阻隔性.结果表明:增容剂能显著提高共混物的相容性.与HDPE相...     

SEBS-g-MAH增容PS/PC体系的结构与力学性能

研究了不同配比的聚苯乙烯/聚碳酸酯(PS/PC)共混体系的结构与力学性能及彼此之间的关系,讨论了增容剂氢化苯乙烯-丁二烯共聚物接枝马来酸酐(SEBS-g-MAH)对共混物相容性及力学性能的影响。差示扫描量热分析表明,PS/PC表现出2个玻璃化转变温度(Tg),而PS/PC/SEBS-g-MAH则只有1个Tg。扫描电镜的分析结果表明,PS为连续相,PC为分散相,而且SEBS-g-MAH的加入使PS与PC的界面变得模糊。可见增容剂对共混体系具有明显的增容作用。共混物的冲击强度在PC用量大于30 phr时明显提高,拉伸强度和冲击强度在低PC含量时较纯PS有一定程度的下降,但随PC含量增加又逐渐提高;增容共混物的力学性能比未增容的有较大提高;当PC用量约40 phr时共混物具有最好的综合性能。     

POE-g-SMA的制备及其对PA6/PTFE共混体系的增容作用

通过马来酸酐(MAH)和苯乙烯(St)双单体溶液接枝法制得了增容剂马来酸酐-苯乙烯接枝乙烯-辛烯共聚物(POE-g-SMA),研究发现,接枝率与反应时间、温度、POE/SMA及引发剂用量有关;POE-g-SMA对聚酰胺6/聚四氟乙烯(PA6/PTFE)共混物有很好的增容作用,加入POE-g-SMA后,复合材料的力学性能和摩擦磨损性能得到改善。     

有机磷酸酯盐与羧酸盐复配成核剂对等规聚丙烯性能的影响

以2,2'-亚甲基-双-（4,6-二叔丁基苯基）磷酸钠 （NA-11）和双环[2,2,1]-庚烷-2,3-二羧酸钠 （NA-CA）2种成核剂进行复配,研究复配成核剂对等规聚丙烯（iPP）力学性能和结晶行为的影响。采用双螺杆挤出机为共混设备将成核剂与iPP共混,制备了NA-11/NA-CA/iPP复合材料。通过万能材料实验机、XRD、DSC、偏光显微镜（PLM）对其力学性能、结晶形态、微观结构进行了表征。结果表明:NA-11和NA-CA 2种成核剂复配能够显著提高iPP的拉伸性能和弯曲性能。NA-11和NA-CA复配成核剂诱导iPP形成α晶体。2种成核剂1∶1复配,添加量为0.4wt%时,iPP的结晶峰温度提高了20.3 ℃,结晶度提高了8.8%。PLM显示,NA-11和NA-CA复配成核剂使iPP球晶尺寸明显变小。NA-11和NA-CA复配成核剂具有很好的成核效果,这2种成核剂对改善聚丙烯的结晶性能和力学性能具有协同效应。      

间规聚苯乙烯/高抗冲聚苯乙烯共混物的结晶行为

用双螺杆挤出机制备了间规聚苯乙烯/高抗冲聚苯乙烯(sPS/HIPS)共混物,用差示扫描量热仪和X射线衍射仪研究了HIPS对sPS熔体结晶和冷结晶行为、晶型的影响。结果表明,熔融温度为290℃时,少量HIPS提高sPS熔体结晶温度,但HIPS含量增加降低sPS熔体结晶温度。熔融温度高于300℃时,sPS熔体结晶温度随HIPS含量的增加而降低。熔融温度从290℃提高到300℃,sPS结晶温度降低,结晶热明显增加。sPS冷结晶峰温随HIPS含量增加和扫描速率加快而提高,HIPS对sPS的结晶主要起阻碍作用。退火处理使得sPS和sPS/HIPS生成α和β晶,且随着HIPS含量的增加,α晶含量增大。     

嵌段共聚物在共混体系中的增容作用研究Ⅰ.PS-b-PMMA对PVC/SBS共混体系力学性能的影响

利用一系列分子量和单体组成比不同的聚苯乙烯-聚甲基丙烯酸甲酯两嵌段共聚物(PS-b-PMMA)作为PVC/SBS共混体系的增容剂.通过研究PVC/SBS的组成比、增容剂的用量以及增容剂的分子结构等因素对共混体系力学性能的影响,系统研究了影响增容剂增容效果的各种因素.结果表明,PS-b-PMMA能显著提高共混体系的力学性能.PVC、SBS及PS-b-PMMA三者之间的比例为100∶10～15∶2时,PS-b-PMMA的增容效果最佳;增容剂的分子结构对增容剂的增容效率有重要影响.     

Improvement in the mechanical strength of asymmetric polyolefin model interfaces

The influence of two types of a styrene–ethylene/butylene–styrene (SEBS) triblock copolymer, one as received and the other functionalized with maleic anhydride, on model interfaces of high-density polyethylene (HDPE) and isotactic polypropylene (iPP) was investigated. Using a special preparation technique, it was possible to prevent gross interdiffusion at the interface and to attribute the problem to an adhesion-dominated phenomenon. The weak mechanical strength of the unmodified interfaces, iPP/iPP and HDPE/HDPE, was greatly improved by the triblock copolymer as was shown by the results of a T-peel test. The morphologies of the peeled surfaces of the modified and unmodified interfaces were analysed with light microscopy. The morphology of both model interface systems show differences, thus revealing different processes at the interfaces and thus different interactions of SEBS with iPP and HDPE and a different influence of the functionalization. The best results were achieved using the functionalized SEBS; the influence of functionalization was greater in the HDPE system. The results are in good agreement with a model proposed by the present authors elsewhere for the concentration-dependent role of SEBS in binary iPP/SEBS and ternary iPP/PE/SEBS blends.     

Structure, thermal properties and mechanical properties of sPS-based nanocomposites with and without styrenic elastomer inclusions

Syndiotactic polystyrene (sPS)-based nanocomposites with and without toughener inclusions were successfully prepared. One organo-montmorillonite (20A) and two styrenic elastomers (SBS and SEBS) served as the reinforcing filler and as tougheners, respectively. XRD and TEM results confirmed the achievement of intercalated and partially exfoliated sPS/20A nanocomposites. The presence of SBS or SEBS slightly depressed the dispersibility of 20A. DSC results indicated that 20A inhibited the crystallization of sPS. The presence of SBS or SEBS further retarded the crystallization of sPS; this effect was more apparent with SEBS. The presences of 20A and SBS/SEBS facilitated the formation of α-form sPS crystals. The thermal stability enhancement of sPS/20A nanocomposites was confirmed, and was further improved with the inclusion of SBS or SEBS. The stiffness of sPS increased with the sole addition of 20A. The addition of SBS or SEBS greatly increased the impact strength of the composites, especially with the addition of SEBS. The achievement of toughened sPS-based nanocomposites was confirmed.     

PA6/SEBS/PP-g-MAH的共混改性

用双螺杆挤出机对PA6用SEBS和SEBS／PP-g-MAH进行共混改性,PA6／SEBS／PP-g-MAH比PA6／SEBS的力学性能如拉伸强度、弯曲强度和冲击强度都有不同程度的提高;PA6／SEBS／PP-g-MAH比PA6／SEBS、PA6的吸水率有较大幅度降低;用扫描电镜(SEM)研究了PA6／SEBS／PP-g-MAH争PA6／SEBS样品的冲击断面,PA6／SEBS／PP-g-MAH中SEBS分散相粒子半径远比PA6／SEBS中SEBS分散相粒子半径小争均匀,这表明PA6／SEBS／PP-g-MAH改性后的PA6与SEBS的相容性有很大的改善。     

LDPE/SEBS共混型形状记忆聚合物的结构与性能

以苯乙烯-乙烯-丁烯-苯乙烯嵌段共聚物(SEBS)热塑性弹性体和低密度聚乙烯(LDPE)为主要原料,采用硫化工艺制备了LDPE/SEBS共混型形状记忆聚合物(SMP)。通过DSC、SEM、WXRD分析,测试了试样记忆性能和凝胶度,研究了固定相LDPE/可逆相SEBS配比与共混型SMP结构和性能的关系。结果表明,LDPE/SEBS配比是影响SMP互穿网络相尺寸和形状、SMP结晶度、玻璃化温度、以及SMP形状回复率、形状固定率等记忆特性的重要因素。     

界面相互作用对尼龙6/SEBS共混体系流变行为的影响

利用高压毛细管流变仪研究了SEBS-g-MAH对PA6／SEBS共混体系的流变行为影响，结果表明，PA6／SEBS共混体系的粘度随SEBS增加先降低后升高；PA6／SEBS—g—MAH共温体系的粘度随SEBS-g—MAH含量增多有较大幅度的增加；将SEBS和SEBS—g—MAH混合使用时，共温材料的流变行为表现为二者的协同作用结果，其中SEBS—g—MAH对共混材料流变性能的影响更大．红外分析的结果表明，共混后SEBS—g—MAH与尼龙6发生了反应，生成群离羧酸，并且随SEBS—g—MAH含量的增加，游离羧酸的量也逐渐增加，即共混后增加了体系中分子键长度，流动时分子键间更易发生缠结，使粘度增加，这与高压毛细管流变实验的结果是对应的。     

Parallel carbon nanotube stripes in polymer thin film with tunable microstructures and anisotropic conductive properties

It is known that shear-flow can induce units to assemble into vorticity-aligned stripe-structures in confined geometries. This study shows that the microstructure and the property of the stripe in polymer thin film can be well tuned by adjusting the viscosity ratio between dispersed phase and continuous phase. Polypropylene (PP)/poly(styrene–ethylene/butadiene–styrene) (SEBS)/octadecylamine functionalized multiwalled carbon nanotubes (ODA-MWCNTs) composites with different viscosity ratios were prepared by either pre-compounding ODA-MWCNT into PP or SEBS in a microcompounder. Under the induction of shear-flow, ODA-MWCNT and SEBS spontaneously assembled into vorticity-aligned stripes in PP thin films for all the composites with different viscosity ratios, resulting in the property of conductive anisotropy for the film. Interestingly, it was found that both the microstructures and the electrical properties of MWCNT stripes in PP thin films prepared from the composites with different viscosity ratios were significantly different.     

Influence of compatibilizing system on morphology,thermal and mechanical properties of high flow polypropylene reinforced with short hemp fibers

Simultaneous influence of polypropylene-graft-maleic anhydride (MAPP) and silane-treated hemp fibers (HF) on morphology, thermal and mechanical properties of high-flow polypropylene (PP) modified with poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS) was studied in this paper. The addition of SEBS reduced the efficiency of MAPP in PP composites with HF, thus silane-treated fibers (HFs) were used to improve polymer–fiber interface. Thermal stability of HF was improved after silane treatment and less than 2% weight loss was observed at 240 °C in composites with 30 wt% HF. Better dispersion of fibers and better efficiency in enhancing static and dynamic mechanical properties of PP, doubling its strength and stiffness were observed in composites with treated fibers compared to untreated ones. High ability to absorb and dissipate energy and well-balanced strength and stiffness were showed by PP modified with SEBS and MAPP containing 30 wt% HFs. These composites were studied as an alternative to conventional PP/glass fibers composites for injection molding of small to medium auto parts.     

AAS/PA-6合金的相容性

用反应挤出法制备了一系列的尼龙６／苯乙烯丙烯酸丁酯丙烯腈共聚物（ＰＡ６／ＡＡＳ）合金的相容剂,采用透射电子显微镜（ＴＥＭ）观察了所得合金的微观形态,结合合金的力学性能,对所选用及所制备相容剂进行了筛选。结果表明,以ＳＥＢＳ与ＭＡＨ的接枝物作为相容剂（ＳＥＢＳ是苯乙烯,丁二烯的三嵌段共聚物）,或以ＳＥＢＳ的ＭＡＨ接枝物与ＳＭＡ（苯乙烯马来酸酐聚合物）作为复合相容剂,既可得到以粘度较高的ＡＡＳ为连续相且冲击强度很高的ＡＡＳ／ＰＡ６合金,也可以得到以ＰＡ６为连续相高冲击强度的ＰＡ６／ＡＡＳ合金。     

反应挤出法制备PPO/PA6/SEBS共混物的研究EI

研究了 PPO- g- MA对 PPO/PA6 /SEBS共混体系的原位增容作用和 SEBS对 PPO/PA6的增韧作用。 PPO/PA6 /SEBS共混物的 TEM结果表明 ,SEBS分散在 PPO中 ,而 PPO又分散在 PA6基体中。 TEM和 SEM的结果均表明 ,PPO- g- MA细化了分散相的相畴 ,增加了界面强度 ;冲击实验的结果表明 ,PPO- g- MA和 SEBS的用量分别为 2 0 %～ 2 5 %和 10 %～ 15 %时 。     

Physical and mechanical properties of SEBS/polypropylene nanocomposites reinforced by nano CaCO3

In present study, styrene‐b‐(ethylene‐co‐butylenes)‐b‐styrene triblock copolymer (SEBS) and polypropylene (PP) are prepared. This mixing is followed by adding 3, 5 and 10 wt% of nano CaCO₃. The morphology and thermal behavior of PP/SEBS/nano‐CaCO₃ compounds are characterized by different methods. Scanning electron microscopy micrographs of cryo‐fractured PP/SEBS/nano‐CaCO₃ nanocomposites show that with increasing nano‐CaCO₃ loading, the aggregation becomes worse. However, followed by adding 5 wt% nano‐CaCO₃ into PP/SEBS nanocomposites, nano‐CaCO₃ is homogeneously dispersed in PP matrix. The photomicrograph of transmission electron microscopy confirms that SEBS/PP/nano‐CaCO₃ nanocomposites are formed, as low aggregations of calcium carbonate were well‐dispersed in polymer matrix. With a rise in nano‐filler content, the tensile and impact strength of PP/SEBS/CaCO₃ nanocomposite are fixed while the elastic modulus of PP/SEBS nanocomposites increases followed by adding nano‐CaCO₃ to polymer blend, which could be due to the acceptable nano‐CaCO₃ dispersion quality.