酸酐化LLDPE/PS增容母料对LLDPE/PS/PA6三元共混物结构及性能的影响

结合聚烯烃与聚苯乙烯间的Friedel-Crafts烷基化反应和聚烯烃熔融接枝马来酸酐(MAH)技术,制备了酸酐化线性低密度聚乙烯(LLDPE)/聚苯乙烯(PS)(70/30,质量比)增容母料。以该母料作为多相相容剂,考察了其对LLDPE/PS/尼龙6(PA6)(60/20/20,质量比)三元共混物微观结构、力学性能和流变性能的影响。红外测试结果表明,酸酐化LLDPE/PS增容母料中含有(LLDPE/LLDPE-g-PS)-g-MAH;三元共混物加入母料后有接枝物(LLDPE/LLDPE-g-PS)-gPA6生成。扫描电镜及力学性能测试结果显示,三元共混物加入质量分数为10%母料后两分散相粒径显著减小,三相之间从互相分离转变为互相连接;力学性能明显提高。动态流变测试结果表明,加入母料后三元共混物的储能模量(G')、损耗模量(G″)和复数黏度(η*)上升,损耗因子(tanδ)减小;三元简单共混物出现2个内耗峰,母料的增容作用可使2个内耗峰均消失。     

酸酐化LLDPE/PS增容母料对PLA/LLDPE/PS共混物性能的影响

在聚乳酸(PLA)/聚苯乙烯(PS)/线型低密度聚乙烯(LLDPE)(质量比40:30:30)共混物中加入酸酐化LLDPE/PS(质量比50:50)增容母料,考察增容母料用量对共混物力学性能、热性能、动态流变性能、微观形貌和孔径分布的影响。红外分析表明,共混体系加入酸酐化增容母料后有(LLDPE-g-PS)-g-PLA接枝共聚物生成;力学性能测试表明,在加入质量分数10%的增容母料后,相较于简单共混物,其拉伸强度提高了160.5%,断裂伸长率提高了184%,继续增大增容母料用量,力学性能提升并不明显;热性能分析表明,共混物中的PLA相结晶规整度提高,加入10%增容母料后,PLA的熔点(T_m)上升了2.03℃,LLDPE的结晶温度(T_C)上升了1.23℃;动态流变测试结果表明,随着增容母料用量的增大,共混物的储能模量(G’)、损耗模量(G’’)和复数黏度(η*)均有上升,损耗因子(tanδ)下降;扫描电镜分析表明,加入增容母料使共混物相分散均匀、相尺寸减小;压汞仪测试表明,共混物经正庚烷、环己烷抽提后,遗留的“PLA”形成了分级多孔结构,增容母...     

(PS-g-LLDPE)-g-MAH增容PA6/LLDPE/PS三元共混物的微观结构及力学性能EI北大核心CSCD

以(聚苯乙烯(PS)-g-线型低密度聚乙烯(LLDPE))-g-马来酸酐(MAH)为相容剂,改变混合方法,制备了具有不同微观结构的尼龙6(PA6)/LLDPE/PS(60/20/20,质量分数)三元共混物。根据热力学、动力学因素,预判了共混物的微观结构;再结合扫描电镜和力学性能测试,考察了微观结构对力学性能的影响。结果表明,简单共混时,因界面张力的作用,在PA6中PS会包裹LLDPE形成壳核结构;该增容剂黏度大,增容时合适的混合方法,使其更易扩散至相界面,有利于阻碍PS包裹LLDPE,使两相独立分散;预判结果与测试结果相一致;壳核结构的出现,会掩盖LLDPE(核)的韧性,使材料呈现出硬而脆的特点;两相独立分散,在保证材料刚性的同时又能提高韧性;采用(PS-g-LLDPE)-g-MAH先与PS、LLDPE混合再与PA6混合的共混法时,增容效果最好,其缺口冲击强度相较于简单共混物提高了近5倍,材料整体表现出硬而韧的特点。     

(PS-g-LLDPE)-g-MAH增容PA6/LLDPE/PS三元共混物的微观结构及力学性能

以(聚苯乙烯(PS)-g-线型低密度聚乙烯(LLDPE))-g-马来酸酐(MAH)为相容剂,改变混合方法,制备了具有不同微观结构的尼龙6(PA6)/LLDPE/PS(60/20/20,质量分数)三元共混物。根据热力学、动力学因素,预判了共混物的微观结构;再结合扫描电镜和力学性能测试,考察了微观结构对力学性能的影响。结果表明,简单共混时,因界面张力的作用,在PA6中PS会包裹LLDPE形成壳核结构;该增容剂黏度大,增容时合适的混合方法,使其更易扩散至相界面,有利于阻碍PS包裹LLDPE,使两相独立分散;预判结果与测试结果相一致;壳核结构的出现,会掩盖LLDPE(核)的韧性,使材料呈现出硬而脆的特点;两相独立分散,在保证材料刚性的同时又能提高韧性;采用(PS-g-LLDPE)-g-MAH先与PS、LLDPE混合再与PA6混合的共混法时,增容效果最好,其缺口冲击强度相较于简单共混物提高了近5倍,材料整体表现出硬而韧的特点。     

PBT/(POE/LLDPE)-g-GMA共混物的力学性能与形态结构

采用双螺杆挤出机将甲基丙烯酸缩水甘油酯(GMA)同时接枝到乙烯-辛烯共聚物(POE)和线性低密度聚乙烯LLDPE上,而后将接枝产物与聚对苯二甲酸丁二醇酯(PBT)反应性共混,通过改变POE/LLDPE比例确立了PBT/(POE/LLDPE)-g-GMA共混物分散相的最佳组成。以此为基础考察了GMA加入量对共混物的力学性能、流变行为及相形态的影响,并对共混物的形变机理进行了研究。实验结果表明,POE/LLDPE比例为50/50时冲击强度最大,在此组成下共混物的冲击强度随着GMA加入量的增加而呈现先增大后减小的趋势,并在GMA加入量(GMA/(POE+LLDPE))为5%时达到最大值;体系黏度随GMA加入量的增加而增大,过量的GMA会导致严重的交联,不利于分散相的分散,从而降低了增韧效率;橡胶粒子的空洞化促使基体发生剪切屈服是其主要的形变机理,LLDPE的引入能促进PBT发生进一步形变,从而提高增韧效率。     

PS/POE增容母料对SAN/PS/POE共混物结构及性能的影响

利用Friedel-Crafts烷基化反应制备了聚苯乙烯(PS)/聚烯烃弹性体(POE)(50/50,质量比,下同)增容共混物。抽提结果显示,该共混物中PS-g-POE接枝共聚物的质量分数为28.3%。以该共混物作为增容母料,考察其对苯乙烯-丙烯腈共聚物/聚苯乙烯/聚烯烃弹性体(SAN/PS/POE)共混体系力学性能、热稳定性、微观结构等方面的影响。结果表明,固定SAN/PS/POE共混物组成,部分PS、POE组分被增容母料取代后,共混物性能得到明显提高,共混物SAN/PS/POE(50/20/30)与SAN/母料/POE(50/40/10)相比,其拉伸强度从10.8 MPa上升至21.0 MPa,断裂伸长率从1.6%上升至22.3%;热重分析显示,增容共混物中易分解组分的热稳定性提高,共混物SAN/PS/POE(20/10/70)与SAN/母料/POE(20/20/60)相比,其易分解组分的分解温度从413.6℃提高到425.1℃;从扫描电镜(SEM)照片可以看出,增容共混物中分散相更均匀细小。     

HIPS/PPO/PS/PB-g-PS共混物的力学性能与形态结构

采用乳液接枝聚合技术在粒径300nm的聚丁二烯(PB)乳胶粒子上接枝苯乙烯(St),制备了核壳比(PB与PS的质量比)为70/30的PB-g-PS接枝共聚物。将其与高抗冲聚苯乙烯(HIPS)、聚苯醚(PPO)和聚苯乙烯(PS)树脂进行熔融共混制得了一系列HIPS/PPO/PS/PB-g-PS共混物,研究了PPO/PS的组成对共混物力学性能和形态结构的影响。结果发现,在HIPS/PPO/PS共混体系中引入PB-g-PS后,HIPS中的大粒径橡胶粒子(2μm~4μm)和PB-g-PS小粒径橡胶粒子(300 nm)具有良好的协同增韧作用;随着基体中PPO含量的增加,共混物的冲击强度、拉伸强度和断裂伸长率均呈上升趋势;当PPO/PS质量比在25/75~50/50范围内3时,共混物冲击强度出现突变式增大,由300 J/m提高至600 J/m。形态结构研究结果表明,随着基体中PPO含量增加,PB-g-PS弹性体粒子在基体中的分散程度获得明显改善;当PPO质量分数低于10%时,主要为银纹屈服形变;当PPO质量分数高于20%时,主要为剪切屈服形变。     

聚苯乙烯/纳米二氧化钛复合材料的制备与表征

利用单螺杆挤出机和平板硫化机制备了聚苯乙烯/纳米二氧化钛(PS/纳米TiO₂)的共混物。研究了PS/纳米TiO₂(100/1.5)中聚苯乙烯接枝马来酸酐(PS-MAH)加入量对共混物的拉伸强度、冲击强度、微观结构的影响。结果表明:当PS-MAH加入PS/纳米TiO₂中20g时,共混物的拉伸强度达到最大值。紫外光照射实验结果表明,PS-MAH的加入可有效地提高PS/纳米TiO₂复合材料的抗老化性能,与PS/TiO₂复合材料相比拉伸强度提高30%。     

PS/粉末SBR-g-S共混体研究Ⅱ.粉末SBR-g-S的相结构及其与PS的相容性

测定了SBR-g-S的接枝率,用TEM检测了粉末SBR-g-S(PR)的相结构.用DSC测定了PS/PR共混体的Tg,研究了PS/PR共混体的相容性.结果发现,在接枝率为32.6%的粉末非交联SBR-g-S(PR1)的相结构中SBR为连续相,在连续相中均匀分布着直径约0.01 μm的PS微区;PS为细胞状分散相,粒径1～5 μm,分散相含有SBR包藏物.在接枝率为8.5%的粉末交联SBR-g-S(PR2)的相结构中PS为连续相,SBR为分散相,分散相粒径约0.3 μm.共混体PS/PR1的相容性优于PS/PR2.SBR在PS富相中有较高的含量是导致PS/PR1共混体在冲击断裂时发生剪切屈服的主要原因.     

路易斯酸用量对POE/PS间Friedel-Crafts烷基化反应及共混物力学性能的影响

用IR,DSC,GPC研究了聚苯乙烯(PS)与聚烯烃弹性体(POE)大分子之间的F riede l-crafts烷基化反应。结果表明:在无水A lC l3催化作用下,PS与POE间可发生质子取代反应生成接枝共聚物POE-g-PS,其接枝百分比随A lC l3用量增加先上升后下降;过量的催化剂会导致聚合物降解;接枝共聚物对POE/PS共混物具有明显的就地增容作用,对于POE/PS/A lC l3=50/50/0.2(质量比)共混物,其拉伸强度与简单共混体系相比,提高了4倍,断裂伸长率提高了10倍。     

F-C烷基化反应原位增容工艺对PS/LLDPE合金结构与性能的影响

在熔融状态下,利用无水AlCl3引发大分子之间的Friedel-Crafts烷基化反应来增容聚苯乙烯(PS)/线性低密度聚乙烯(LLDPE)(80/20)合金。研究了"一步法"和"两步法"增容工艺对PS/LLDPE合金结构和性能的影响。结果表明,以"一步法"增容PS/LLDPE(50/50)合金40份为母料,与60份聚苯乙烯混合("两步法")制备PS/LLDPE(80/20)合金,可有效地降低聚苯乙烯降解对合金性能的影响,提高合金的热稳定性和力学性能;从扫描电镜(SEM)照片可以看出,"两步法"制备的合金的分散相更加均匀细小,韧性断裂特征明显。     

PS/EPDM就地相容化

采用扭矩分析、凝胶含量和力学性能测定、共混物热分析、界面形态观察等方法考察了无水AlCl3用量对聚苯乙烯（PS）和乙丙三元橡胶（EPDM）大分子间Friedel-Crafts烷基化反应的影响。结果表明,加入适量的无水AlCl3可以引发PS、EPDM间的Friedel-Crafts烷基化反应,生成的EPDM-g-PS接枝...     

The effect of compatibilizers on the morphology of isotactic polypropylene/linear low-density polyethylene blends

The morphology of isotactic polypropylene (iPP)/linear low-density polyethylene (LLDPE) blends, compatibilized with ethylene-propylene block copolymer (EP) and two types of styrene-ethylene/butylene-styrene triblock copolymer (SEBS), one containing maleic anhydride, the other no reactive sites, has been investigated by using small-angle X-ray scattering by evaluating their interface distribution functions. To characterize the crystallization behaviour of the blends, their spherulitic growth rates have been measured under the polarizing microscope and nucleation and crystallization kinetics data have been evaluated. The addition of LLDPE to iPP alone has a pronounced effect on the lamellar morphology of the iPP. Adding compatibilizer to the iPP/LLDPE blend leads to a further decrease of the lamellar thickness. Concurrently the nucleation density increases while the Avrami exponent drops from n2.3 for iPP to n=0.74 for the iPP/LLDPE/SEBS blend. It is concluded that the compatibilizer causes the polyethylene component to become more highly dispersed in the polypropylene matrix.     

Toughening effect of maleic anhydride grafted linear low density polyethylene on linear low density polyethylene

The blend of linear low density polyethylene (LLDPE) and maleic-anhydride grafted LLDPE with the grafting degree of 1.3% and the gel content of 27.0% (designated as LLDPE/MA-PE) was melt-compounded. Their thermal, rheological, and mechanical properties were studied. The crystallization temperature and crystallization rate of LLDPE/MA-PE blends increase due to the nucleation of MA-PE, their crystallinity is between those of LLDPE and MA-PE due to the balance between the nucleation of MA-PE and simultaneously produced more defects. The addition of MA-PE increases the apparent viscosity of blend melts, but the shear-sensitivity of blends provides them with melting processing. Interestingly, the lamellar crystallites induced by MA-PE decrease the tensile yielding strength of LLDPE/MA-PE blends. During the impact fracture, the formation of oriented crystalline lamellae parallel to the crack front and perpendicular to the crack flank, leads to the deformation and microstriations in LLDPE/MA-PE blends. Subsequently, toughness of LLDPE/MA-PE blends is improved.     

Effect of different polypropylenes and compatibilizers on the rheological,mechanical and morphological properties of nylon 6/PP blends

In this work, the rheological, mechanical and morphological properties of nylon 6/polypropylene compatibilized blends were investigated. Two types of polypropylene were used. One with MFI of 40 g/10 min (PP H103) and the other with MFI of 3.5 g/10 min (PP H503). The compatibilizers used were polypropylene grafted with 6% of acrylic acid (PPgAA) and polypropylene grafted with 1% of maleic anhydride (PPgMA). The blends composition was 80/20 (wt%) for the PA6/PP binary blends and 80/10/10(wt%) for the nylon 6/PPgAA/polypropylene and nylon 6/PPgMA/polypropylene ternary blends. Torque rheometry analysis showed that when PPgAA and PPgMA were added to nylon 6/polypropylene blends, there was an increase in the torque, indicating that reactive compatibilization has occurred. There is no influence of the polypropylene MFI on the mechanical properties of the uncompatibilized and compatibilized blends. The impact strength of the blends containing PPgMA were greater than those of the blends containing PPgAA. The blends containing PPgAA are unstable. SEM analysis showed that PPgMA improves considerably the adhesion between PA6/PP phases, leading to good mechanical properties.     

Effect of nanoclay and SEBS-g-MA on the morphology and properties of immiscible poly(methyl methacrylate)/polystyrene blend

In recent years, nanoclays are being used as compatibilizer for various immiscible polymer blends. However, little work has been done on the morphology of immiscible polymer blends in presence of both the nanoclay and a reactive compatibilizer. Here, we report the synergistic effect of nanoclay and SEBS-g-MA on the morphology and properties of (70/30 w/w) PMMA/PS blend. Scanning electron microscopy study of the blend with various amount of nanoclay and SEBS-g-MA indicated a reduction in the average domain sizes (D) of dispersed PS phase in PMMA matrix compared to that in the pure blend. Addition of both SEBS-g-MA and nanoclay significantly lowered the D of PS in the blend compared to that with only SEBS-g-MA or clay. X-ray diffraction study and transmission electron microscopy revealed the presence of intercalated clay platelets in PMMA matrix, as well as, at the interface of the (70/30 w/w) PMMA/PS blend-clay nanocomposites. Addition of SEBS-g-MA in the blend-clay nanocomposites promoted the exfoliation of clays in PMMA matrix. Thus, exfoliated clay platelets in PMMA matrix effectively restricted the coalescence of dispersed PS domains while SEBS-g-MA improved the adhesion between the phases at the interface. At certain loading (phr), storage modulus, elongation at break and thermal stability of the blend were greatly improved when both the nanoclay and SEBS-g-MA were present in the blend. The use of reactive compatibilizer and nanoclay in polymer blends may lead to a high performance material which combines the advantages of compatibilized polymer blends and the merits of polymer nanocomposites.     

PVC／LLDPE共混体系形态结构的控制

采用氢化聚丁二烯－ｂ－甲基丙烯酸甲酯（ＰＢＤ－ｂ－ＰＭＭＡ）共聚物作为聚氯乙烯／线性低密度聚乙烯（ＰＶＣ／ＬＬＤＰＥ）共混体系的增容剂，用扫描电子微镜（ＳＥＭ）和透射电子显微镜（ＴＥＭ）对共混体系的冲击缺口断面和相结构进行了研究。并用小角激光菜射技术了ＬＬＤＰＥ在共混物中的结晶行为，发现增容剂对共混体系的形态结构会产生极大的影响。     

尼龙结构对尼龙/聚乙烯共混物织构形态的影响

比较了尼龙６／线型低密度聚乙烯（ＰＡ６／ＬＤＰＥ）和尼龙１０１０／线型低密度聚乙烯（ＰＡ１０１０／ＬＬＤＰＥ）共混和的织构形态,共混物的织构形态除与织构调节剂、组分比有关外,还与尼龙物结构有很大关系。在尼龙／聚乙烯二元共混物中,分散相粒子以球状（或椭球状）形式存在,粒子较大,两相界面清晰,加入织构调节剂后,分散相粒子明显变小,分布均匀,在尼龙６共混物中,除仍有表面光滑的球状粒子外,出现了莲藕断面状粒子,但两相之间仍有缝隙,而在尼龙１０１０共混物中,出现了辐（车）轮状粒子,两相间相互作用强,分散相粒子与连续相之间紧紧地连接在一起,表明高碳数的尼龙１０１０与聚乙烯的链段间的相容性更好。     

SEBS-g-MA对R-PET/LLDPE共混物结构与性能的影响

以SEBS-g-MA为相容剂,借助力学性能、DSC、SEM和DMA等表征手段对SEBS-g-MA在R-PET/LLDPE/SEBS-g-MA共混物中的作用进行研究。研究发现,添加质量分数10%的SEBS-g-MA时,共混物的缺口冲击强度和断裂伸长率都得到明显的改善。DSC分析结果表明,LLDPE和PET的熔点都没有发生变化,但PET的熔融峰出现双峰。SEM结果显示,添加10%SEBE-g-MA能够使LLDPE在PET基体中充分分散,过量的SEBS-g-MA会诱导部分PET进入分散相,最终形成Salami结构的聚集体。     

Impact essential work of fracture toughness of ABS/polyamide-6 blends compatibilized with olefin based copolymers

The impact fracture toughness of acrylonitrile-styrene-butadiene/polyamide-6 (ABS/PA6) blends compatibilized with 5% by weight carbon monoxide modified ethylene-n butyl acrylate-maleic anhydride (EnBACO-MAH) or ethylene-methyl acrylate-glycidyl methacrylate (EMA-GMA) copolymers were examined as a function of blend ratio by standard Charpy tests, Essential Work of Fracture (EWF) Methodology and fracture surface morphologies. The samples were first processed in twin-screw extruder and they were subsequently injection moulded. The incompatibilized blends and neat-PA6 fractured in brittle manner, whereas compatibilized blends fractured in ductile manner. The EWF values yielded a maximum when weight percentages of ABS and PA6 were equal to each other. The values obtained in the case of EnBACO-MAH were higher than that of EMA-GMA regardless of blend composition in EWF tests. The trend of impact strengths observed in standard notched Charpy impact tests was in accordance with that of EWF values of blends. The morphology of the ABS/PA6 blends exhibited differences as a function of the component ratio and compatibilizer type. These differences in topology of the fracture surfaces of the blends were utilized to understand the deformation mechanism, and to correlate the fracture toughness values of the blends.