环氧类增容剂反应增容PLA/PBAT共混体系的研究

以环氧类增容剂(REC)为增容剂,采用双螺杆挤出机熔融共混制备聚乳酸(PLA)/聚对苯二甲酸己二酸丁二醇酯(PBAT)共混物。研究了增容剂对共混体系微观结构、力学性能和热性能的影响。结果表明,添加适量REC可以提高PLA与PBAT的相容性,改善PLA/PBAT共混体系的综合力学性能;REC用量为1.4份时共混体系呈现出良好的相容性,此时共混物冲击强度由268 kJ/m2增加到621 kJ/m2、断裂伸长率提高由222 %增加到357 %。     

PS-g-MAH的制备及其增容PS阻燃复合材料的研究

以聚苯乙烯(PS)为载体,马来酸酐(MAH)为接枝单体,过氧化二异丙苯(DCP)为引发剂,采用熔融接枝法制备了聚苯乙烯接枝马来酸酐共聚物(PS-g-MAH)。考察了MAH用量、DCP用量对PS-g-MAH接枝率的影响。经红外光谱(IR)表征,接枝物为目标产物。将接枝率为3.7%的PS-g-MAH作为PS/膨胀阻燃剂/热塑性弹性体复合材料的增容剂,探讨了增容剂对该复合材料阻燃、力学和加工性能及微观结构的影响。结果表明,当增容剂用量为12份时,冲击强度达到4.89 kJ/m2,比未增容时提高了87.4%,拉伸强度仍可保持在21.3 MPa。在力学性能得到改善的同时,复合材料的垂直燃烧可达到FV-0级,氧指数由27.1%提高到了27.9%,熔体质量流动速率为4.62g/10min。     

TPU/PA1212/joncryl复合材料的制备与性能

通过熔融共混方法制备了热塑性弹性体聚氨酯(TPU)/聚酰胺1212(PA1212)/joncryl共混物.研究了增容剂joncryl含量对共混物力学性能、热性能、结晶度和耐磨性的影响.力学性能测试表明:共混物的拉伸强度从25.13 MPa增加至27.18 MPa,弯曲强度从21.51 MPa逐渐增加到23.70 MPa...     

管材用回收高密度聚乙烯/胶粉复合材料的研究

采用一步法活化增容制备了回收高密度聚乙(烯RHDPE/)胶粉管材专用料,并研究了引发剂过氧化二异丙苯强度从37.5 kJ/m2提高到48 kJ/m2;弯曲强度从10.5 MPa提高到12.9 MPa;弯曲模量从356 MPa提高到405(DCP)、接枝单体马来酸酐(MAH用)量对体系力学性能的影响。结果表明:当DCP、MAH用量分别为0.1份、1.0份时,RHDPE/胶粉体系获得最佳的力学性能,与简单共混物比较,拉伸强度从18.8 MPa提高到23.8 MPa;缺口冲击MPa。通过流变性能测试结果和扫描电(镜SEM)照片分析活,化增容对RHDPE/胶粉体系有效。     

强拉伸场诱导PP/TPU复合材料纤维化结构的形成及性能研究

通过熔融共混的方法制备了聚丙烯/聚氨酯(PP/TPU)复合材料，TPU在PP/TPU复合材料中呈现“海-岛”结构分布，导致复合材料具有较低的力学强度。通过施加强拉伸场，PP/TPU复合材料的相对结晶度显著提高，并且随着拉伸比的增加，复合材料的结晶度和取向度逐渐增加；此外，通过在PP/TPU复合材料中增容剂的引入，显著改善了TPU在PP基体中的分散性。在较高拉伸比下，PP/TPU复合材料内部能够形成纤维化结构，使PP材料的拉伸强度从约30 MPa(DR=1)提高到了约320 MPa(DR=8),提高幅度约966%。相比于口模拉伸的纯PP材料，TPU和增容剂的引入能够使口模拉伸的复合材料在具有较高拉伸强度的同时，具有较好地韧性。因此，通过协同调控口模拉伸成型强拉伸场和增容剂，可以获得同时增强增韧的PP复合材料，为PP的改性提供了一种新的方法。     

反应性增容制备高性能PLA/PA11共混物

由于聚乳酸(PLA)与尼龙11(PA11)的相容性较差,因此,利用熔融接枝法制备了PLA与甲基丙烯酸缩水甘油酯(GMA)的接枝物PLA-g-GMA,并充当共混物的增容剂。在共混的过程中,利用增容剂原位反应性,增容PLA与PA11的共混体系。对共混物进行力学性能测试,结果表明,在没有添加增容剂的条件下,共混物的力学性能较差;随着接枝物的加入,共混物的力学性能显著提高。在PLA/PA11(80/20)组分中,当增容剂的含量达到20%时,共混物的断裂伸长率和拉伸强度均达到了最大值分别为281. 14%、53. 16 MPa,且材料抗冲击性能也有一定的改善,与纯PLA相比,增加了132%。     

增容剂对PP/PP-g-MAH/CaCO_3复合材料性能与形态的影响

采用熔融混合法制备了PP/PP-g-MAH/CaCO3复合材料,并利用万能试验机、差示扫描量热仪(DSC)和扫描电子显微镜(SEM)分析了PP-g-MAH含量对PP/PP-g-MAH/CaCO3复合材料力学性能、结晶性能与界面形态的影响。结果表明:随着增容剂PP-g-MAH含量的增加,PP/PP-g-MAH/CaCO3复合材料的拉伸强度从25.7 MPa增加到32.0 MPa,弯曲强度从34.7 MPa增大到41.2 MPa;结晶温度则先增大后逐渐减小,当PP-g-MAH含量为2%时结,晶温度为123.9℃,结晶度为44.7%;而断裂伸长率和冲击强度逐渐减小。     

柠檬酸原位增容聚苯醚/尼龙66合金的研究

为解决聚苯醚(PPE)和尼龙66(PA66)的相容问题,选用柠檬酸进行原位增容,采用两种不同的挤出共混方式制备PPE/PA66合金,并与现有增容剂PPE-g-MAH的增容效果进行了对比。考察增容剂对合金力学性能和微观形貌的影响,并探讨柠檬酸的增容机理。结果表明,柠檬酸原位增容时,选用两步挤出工艺,能够得到力学性能优良的合金,当柠檬酸用量为1份时,合金的拉伸强度为70.31 MPa,弯曲强度为89.23 MPa,冲击强度为15.76 kJ/m2。用柠檬酸原位增容时,合金的分散相尺寸明显减小,均匀性得到改善。。     

聚乳酸/聚酰胺弹性体/聚乙酸乙烯酯共混纤维的制备及性能研究

以聚乙酸乙烯酯(PVAc)为增容剂,采用熔融共混和熔融纺丝的方法制备了聚乳酸(PLA)/聚酰胺弹性体(PAE)/PVAc共混切片和共混纤维,研究了增容剂的加入对共混切片相容性的影响和共混纤维増韧改性效果的影响。结果表明,加入PVAc后,分散相粒子尺寸减小,两相界面模糊,相容性提高。随着PAE弹性体含量增加,初生纤维中PLA的结晶度提高;二级牵伸共混纤维在PAE含量为10%时,综合力学性能最优,断裂强度、模量、断裂伸长率和断裂功分别达412.7 MPa、6 345.4 MPa、22.3%和127.4 mJ,共混纤维的可纺性显著提高。     

PUR-T增韧POM复合材料的制备及其性能

以聚甲醛(POM)为基体,以热塑性聚氨酯弹性体(PUR-T)为增韧剂,二苯基甲烷二异氰酸酯(MDI)为增容剂,制备了增韧POM复合材料。研究结果表明,聚酯型PUR-T对POM的增韧效果优于聚醚型PUR-T。POM复合材料的冲击强度和断裂伸长率随着PUR-T含量的增加而增大,当PUR-T质量分数为20%时,复合材料的缺口冲击强度达到21.1 k J/m2,是纯POM的3倍,断裂伸长率达到273%,约是POM的12倍。通过对不同类型增容剂的优选,发现MDI能够实现有效增容,优于其它类型的增容剂,当PUR-T质量分数为10%,MDI质量分数为3%时,复合材料的断裂伸长率由26.4%提高到43.9%,提高了66.3%,增容剂MDI能够有效提高PUR-T与POM的相容性,能够有效起到增容作用。     

低硬度CM／EVA TPV的制备及性能

采用动态硫化法制备了氯化聚乙烯橡胶（CM）／乙烯一醋酸乙烯共聚物（EVA）热塑性硫化胶（TPV）,对其力学性能和动态粘弹行为进行了研究。结果表明：在实验范围内,动态硫化CM／EVATPV呈现出典型弹性体软而韧的应力一应变行为,当CM／EVA的共混质量比在80／20～60／40之间时,所制备的低硬度TPV表现出了良好的综合性能。橡胶加工分析仪（RPA）的研究表明,随着扫描频率的增加,CM／EVATPV的储能模量呈线性增长趋势,损耗因子则呈下降趋势;随着应变的增加,TPV表现出明显Payne效应,储能模量发生大幅度下降,损耗因子在应变大于10．O％后急剧增加。     

热塑性弹性体在封边热熔胶中的应用

制备出增韧家具封边热熔胶,主要组分为EVA树脂、热塑性弹性体A、松香衍生物、松香、填料等。经检测,软化点92℃,拉伸强度大于4 MPa,断裂伸长率150%,原材料成本低于10元/kg。     

TPS/EVA泡沫复合材料的制备及其阻燃与力学性能

以热塑性淀粉(TPS)为成炭剂与聚磷酸铵(APP)、可膨胀石墨(EG)复配组成膨胀型阻燃剂,通过熔融密炼、开炼塑化、硫化发泡制备了热塑性淀粉/乙烯-醋酸乙烯酯共聚物(TPS/EVA)泡沫复合材料,探讨了TPS用量对泡沫复合材料阻燃性能、力学性能的影响。结果表明,TPS的加入显著提高了TPS/EVA泡沫复合材料阻燃性能,可起到良好的成炭作用;TPS/EVA泡沫复合材料的拉伸强度、断裂伸长率以及撕裂强度随着TPS用量的增加呈现先增大后减小的趋势,相对密度则是小幅度上升。当TPS用量为6%时,TPS/EVA泡沫复合材料综合性能最好,其LOI可达26.5%且UL-94为V-0级,拉伸强度、断裂伸长率、撕裂强度以及相对密度可达2.395 MPa、177.48%、10.59 N·mm^-1、0.21452。     

正交试验法制备热塑性低烟无卤阻燃聚烯烃电缆料

用正交试验法研究了不同醋酸乙烯(VA)含量的乙烯-醋酸乙烯共聚物(EVA)的不同配比、氢氧化镁(MH)及滑石粉的用量对以EVA为基础树脂的热塑性低烟无卤阻燃电缆料性能的影响。结果表明:EVA为100phr,表面处理的MH为80phr,滑石粉为20phr时,材料的氧指数达到了43%,拉伸强度为8.3MPa,断裂伸长率为550%,低温冲击脆化温度达到-30℃。满足热塑性低烟无卤阻燃聚烯烃电缆料的性能要求。     

不同热塑性弹性体增韧聚甲醛

在比较乙烯-辛烯共聚热塑性弹性体(POE)、氢化苯乙烯-丁二烯-苯乙烯嵌段共聚物(SEBS)和凝胶丁腈弹性体(GNBE)增韧聚甲醛(POM)的力学性能基础上,研究了GNBE增韧POM共混物的应力一应变、断裂形貌和热稳定性。结果表明,以GNBE改性POM共混物的力学性能最好。当以质量分数为6％的酚醛树脂为增容剂时,用质量分数为20％的GNBE增韧POM,共混物缺口冲击强度为21．6kJ／m^2,扯断伸长率为133．0％,拉伸强度为33．8MPa。当GNBE质量分数为10％时,POM／GNBE共混物应变为未改性POM的2倍。试样缺口冲击断裂形貌分析表明,POM的断裂表面光滑平整,是典型的脆性断裂;而POM／GNBE共混物的断裂表面粗糙。加入质量分数为20％,的GNBE,POM／GNBE共混物在空气气氛中的热失重温度有明显的提高。     

New thermoplastic vulcanizate,composed of polypropylene and ethylene–vinyl acetate copolymer crosslinked by tetrapropoxysilane: evolution of the blend morphology with respect to the crosslinking reaction conversion

A thermoplastic vulcanizate (TPV) is tailored by a dynamic vulcanization process. TPVs can be processed as thermoplastics and have properties similar to conventional vulcanized rubbers. The main objective of our recent works was to tailor, by using the reactive extrusion process, a new TPV composed of polypropylene homopolymer (PP) as thermoplastic phase and ethylene–vinyl acetate copolymer (EVA) as elastomer phase, which is crosslinked by tetrapropoxysilane (TPOS) as crosslinking agent in the presence of dibutyl tin oxide (DBTO) as catalyst. Crosslinking is carried out through a transesterification reaction between the ester groups of EVA and the alkoxysilane groups of TPOS. This exchange reaction is catalyzed by DBTO at temperatures above 100 °C. The main advantage of this chemistry that it is non‐radical, and so prevent the degradation of PP, in comparison with crosslinking reactions using peroxides as initiators. Different reactive blends were prepared in the internal mixer of a Haake Plasticorder. In order to know how the crosslinking reaction has advanced, the EVA gel content and the volume swelling rate of the blend were measured. The aim of this study was to get a better understanding of the dispersion mechanism of EVA in the major phase during its dynamic vulcanization in the presence of PP in the minor phase. This paper deals with the correlation that exists between the evolution of the two‐phase blend morphology and the extent of the crosslinking reaction on the elastomer phase during the elaboration of a TPV. In particular, we showed that the correlation was almost the same for the elaboration of the TPV in the internal mixer of the Haake Plasticorder (discontinuous process) and in a twin‐screw extruder (continuous process). Copyright © 2004 Society of Chemical Industry     

热塑性聚酰胺弹性体改性EVA复合发泡材料的制备及性能表征

研究了发泡剂用量对热塑性聚酰胺弹性体(TPAE)改性乙烯-醋酸乙烯共聚物(EVA)复合发泡材料(EVA/TPAE)的影响,并在最佳发泡剂用量下探究了EVA中TPAE的添加量对EVA/TPAE复合发泡材料发泡性能及力学性能的相关影响.结果表明,EVA/TPAE=100:5(质量比,下同)时,EVA/TPAE共混物/发泡剂...     

苯乙烯类热塑性弹性体的生产现状及发展趋势

苯乙烯与二烯烃嵌段共聚物类热塑性弹性体因性能优良而得到迅速发展,其产量已位居各类热塑性弹性体之首,消耗量占热塑性弹性体的５０％以上,预计今后产量将以年均约８％的速度递增。通过对其改性技术的研究,提高产品质量,降低生产成本,如开发高透明度,等性能优良或用途特殊的新产品。     

BR/EVA TPV的制备及性能研究

采用动态硫化法制备BR/乙烯-乙酸乙烯酯共聚物(EVA)热塑性硫化胶(TPV),并对其性能进行研究.结果表明:当BR/EVA共混比大于50/50时,TPV呈现出典型弹性体的应力-应变行为;当BR/EVA共混比为50/50～65/35时,TPV的硬度较低,综合物理性能良好;当BR/EVA共混比为60/40时,微米级的BR粒状物均匀分散在EVA基体中,两相界面结合良好.     

Ethylene vinyl acetate copolymer/halloysite nanotubes nanocomposites with enhanced mechanical and thermal properties

Ethylene vinyl acetate (EVA) nanocomposites filled with halloysite nanotubes (HNTs) were prepared by melt compounding. The homogenous dispersion of HNTs into the EVA matrix was evaluated by SEM and TEM analysis. The addition of HNTs does not influence on the phase separation structure and crystallinity of EVA nanocomposites. Due to the reinforcing effect of HNTs embedded in the EVA elastomer matrix, along with an increase of HNTs concentration, the improvement in tensile properties, by means of modulus at an elongation of 100% and tensile strength, was observed. It was found that tensile strength increased by 27% for EVA nanocomposite with 8 wt% of the HNTs. The values of elongation at break at low HNTs' loading increase and subsequently at higher loading are comparable to the neat EVA copolymer. The elastic deformability and reversibility of the EVA nanocomposites with different HNTs content was analyzed. The cyclic tensile tests showed that prepared nanocomposites have values of permanent set slightly higher than for neat EVA copolymer. Furthermore, the limiting oxygen index value for the EVA based nanocomposite with the highest HNTs content (8 wt%) increased from 19.5 to 24.8%. The results show, that thermo-oxidative stability were improved by the incorporation of HNTs into EVA copolymer matrix.