PLA／LLDPE共混体系反应性增容研究

在聚乳酸(PLA)中加入线性低密度聚乙烯(LLDPE)进行增韧,并通过相容剂LLDPE接枝甲基丙烯酸缩水甘油酯-苯乙烯共聚物[LLDPE-g-(GMA-co-St)]和弹性体乙烯-甲基丙烯酸-甲基丙烯酸缩水甘油酯(E-MA-GMA)增容PLA和LLDPE.用红外光谱、动态流变和SEM对共混物进行了表征,测试了共混物的力学性能.结果表明,LLDPE-g-(GMA-co-St)和E-MA-GMA的加入都能明显提高PLA/LLDPE的冲击韧性,起到了反应性增容的作用,使共混体系的分散相尺寸明显减小,分布均匀,共混物的动态损耗模量G"增加.与LLDPE-g-(GMA-co-St)相比,加入E-MA-GMA的共混物中分散相粒径更加细微.     

E-MA-GMA增容剂对PPS/PA66共混体系性能的影响

研究了增容剂乙烯(E)-丙烯酸酯(MA)-甲基丙烯酸缩水甘油酯(GMA)共聚物(E-MA-GMA)对聚苯硫醚(PPS)/聚酰胺(PA)66共混体系的相容性、力学性能、热性能、流变性能的影响。结果表明,增容剂的加入,增加了共混体系的相容性,提高了共混物的力学性能;DSC结果表明,E-MA-GMA影响共混体系的结晶和熔融行为;流变性能测试结果表明,增容PPS/PA66共混体系是假塑性流体,E-MA-GMA用量增加,使共混体系的表观黏度增大。     

酸酐化LLDPE/PS增容母料的制备及其应用

通过Friedel-Crafts烷基化反应和聚烯烃熔融接枝马来酸酐(MAH)技术,制备了酸酐化线型低密度聚乙烯(LLDPE)/聚苯乙烯(PS)增容母料,并用该母料增容LLDPE/PS/聚酰胺(PA)6三元共混物,考察了母料用量对LLDPE/PS/PA 6三元共混物结构及性能的影响。结果表明:酸酐化增容母料中主要含有MAH接枝LLDPE-g-PS与MAH接枝LLDPE,可用于提高LLDPE与PS和PA 6的相容性;该母料能有效增容LLDPE/PS/PA 6三元共混物,使三相之间界面作用增强,分散相粒径显著减小,力学性能提高;随着母料用量增加,共混物的熔体流动速率下降,LLDPE的结晶温度上升,而PA 6的结晶温度和PS的玻璃化转变温度呈下降趋势;当母料用量为8 phr时,共混物的力学性能和耐热性能最佳。     

E-MA-GMA对PLA/LLDPE共混体系的增容性研究

采用SEM、材料力学性能、旋转流变等实验方法考察了乙烯-丙烯酸甲酯-甲基丙烯酸缩水甘油酯三元共聚物(E-MA-GMA)对聚乳酸/线性低密度聚乙烯(PLA/LLDPE)共混体系的微观形态、力学性能以及动态流变性能的影响。结果表明:E-MA-GMA的加入能显著提高PLA/LLDPE的相容性,分散相在PLA基体中有更加细微和均匀的分散,并呈现部分韧性断裂特征,材料冲击韧性显著提高,共混体系的动态损耗模量增大。     

PPS/PA66共混体系流变性能研究

分别以乙烯-丙烯酸甲酯-甲基丙烯酸缩水甘油酯(E-MA-GMA)、苯乙烯-丙烯腈-甲基丙烯酸缩水甘油酯(StAN-GMA)以及苯乙烯-(乙烯-丁烯)-苯乙烯嵌段共聚物接枝马来酸酐(SEBS-g-MAH)为相容剂,采用熔融共混的方法制备了改性聚苯硫醚/聚酰胺66(PPS/PA66)共混物。通过毛细管流变分析,研究了PPS及相容剂用量对PPS/PA66共混物流变性能的影响。结果表明:PPS/PA66共混体系为非牛顿假塑性流体,其表观黏度随剪切速率的增大而减小;随着PPS用量的增加,共混体系的非牛顿指数降低,其流变性能逐渐偏离牛顿型流体;随着相容剂用量的增加,PPS/PA66/E-MA-GMA体系的熔体黏度明显增大,PPS/PA66/St-AN-GMA体系的熔体黏度则先下降后上升,而PPS/PA66/SEBS-g-MAH体系的熔体黏度变化不大。     

PA6相对黏度对PA6/POE-g-MAH共混物缺口冲击性能的影响

研究了尼龙(PA)6相时黏度对PA6/马来酸酐接枝乙烯-辛烯共聚物(POE-g-MAH)共混物缺口冲击性能的影响.结果表明,PA6的相对黏度对PA6/POE-g-MAH共混物的缺口冲击断裂韧性有明显影响;低黏度PA6/POE-g-MAH共混物冲击断裂过程中的裂纹扩展功明显高于中、高黏度PA6/POE-g-MAH共混物;...     

BHDPE/HDPE/LLDPE共混体系的研究

采用线性低密度聚乙烯(LLDPE)对双峰高密度聚乙烯(BHDPE)和高密度聚乙烯(HDPE)进行共混,测定共混物的力学性能和DSC曲线。结果显示共混物均可以产生共晶,LLDPE对BHDPE力学性能影响较大;在LLDPE/HDPE中添加BHDPE,三者共混物具有更好的力学性能,流变性能显示三者共混物体系黏度变化不大,为制备性能最优、成本最低的三者共混物提供了依据。     

原位增容PA6/POE/EVOH共混物的流变性能研究

采用熔融共混法制备了聚酰胺6/乙烯-1-辛烯共聚物/乙烯-乙烯醇共聚物(PA6/POE/EVOH)共混物,利用毛细管流变仪对共混物的流变行为进行了研究。结果表明:PA6/POE/EVOH共混物为假塑性流体,呈现出切力变稀的现象;EVOH的加入增大了PA6/POE/EVOH共混物的表观黏度和黏流活化能,说明共混物对温度的依赖性较强。     

聚烯烃离聚体原位增容PP/LLDPE共混物的研究!

用傅立叶红外光谱(FTIR)、力学性能测试等方法研究了聚烯烃离聚体原位增容聚丙烯/线性低密度聚乙烯(PP/LLDPE)共混物。结果表明:熔融状态下,在马来酸酐接枝聚丙烯/马来酸酐接枝线性低密度聚乙烯(PP-g-MAH/LLDPE-g-MAH)(质量比50/50)共混物中加入二水醋酸锌,共混物中的马来酸酐基团(羧酸基团)与Zn2+发生离子偶联反应,相界面就地产生的聚烯烃离聚体增加了两相界面黏合力,共混物力学性能提高;原位增容后共混物中的PP和LLDPE相熔点略微下降,LLDPE结晶温度向高温移动;在角频率为0.01～100.00s-1,原位增容后共混物的储能模量、损耗模量和复数黏度都高于简单共混物的,损耗正切(tanδ)低于简单共混物的;对于PP/PP-g-MAH/LLDPE/LLDPE-g-MAH四元体系,SEM显示原位增容后共混物的相界面变得模糊,相容性提高。     

HDPE/HDPE-g-MAH/PA11共混物流变行为的研究

以马来酸酐接枝高密度聚乙烯(HDPE-g-MAH)为增容剂,通过熔融共混法制备了HDPE/HDPE-g-MAH/聚酰胺11(PA11)共混物,讨论了增容剂HDPE-g-MAH对共混物流变行为的影响。结果表明:HDPE-g-MAH的加入使共混物熔体对剪切速率的敏感性增强,同时使共混物黏度对温度变化的敏感程度减弱;随着HDPE-g-MAH含量的增加,共混物表观黏度先增加后减小,其含量为2%时共混物黏度最大。     

Polyamide 6 and polyamide 66 blends with functionalized polyolefins: Effect of phenomenal increase in viscosity and melt strength of polyamide 66-based materials

The effect of adding blends of linear low-density polyethylene (LLDPE) and ethylene-octene copolymer (EOC) functionalized by grafting (in the course of reactive extrusion) of trans-ethylene-1,2-dicarboxylic acid (TEDA) onto polyamide 6 (PA6) and polyamide 66 (PA66) on rheological and elastic properties of their melts, structural morphology, and mechanical properties has been studied. It is shown that PA66/functionalized polyolefins (fPO) blends are characterized by more significant changes in the characteristics being analyzed as compared to PA6/fPO blends. A phenomenally sharp increase (by more than two decimal orders of magnitudes) in the melt viscosity of PA66/fPO blend as compared to the initial PA66 was established. At the same time, the melt strength may increase more than 50-fold. The degree of TEDA grafting (β) onto PO macromolecules is the most important parameter determining the level of the values of property indices, as well as the structural features of PA/fPO blends. Only when particular β values (varying in a relatively narrow range) are reached, a quasi-homogeneous morphology is formed in PA/fPO blends and their deformation capacity as well as the impact strength of materials increase dramatically. The observed effects are caused by the influence of TEDA grafting on interphase interactions in PA/fPO and PA66/fPO blends.     

A facile route for preparing stable co-continuous morphology of LLDPE/PA6 blends with low PA6 content

A facile method is employed to prepare a series of LLDPE/PA6 blends with co-continuous morphology with low PA6 content via reactive extrusion. In these blends, co-continuous morphology is obtained by introducing graft copolymers with both high and low molecular weight trunk chains to the interface simultaneously. Maleic anhydride functionalized polybutadine (PB-g-MAH, and MAH content = 10 wt%) is first melt grafted onto the LLDPE backbones with dicumyl peroxide (DCP) as an initiator. Part of PB-g-MAH is grafted onto LLDPE to form LLDPE-g-PB-g-MAH copolymer. During reactive extrusion, in-situ formed Copolymer II (polybutadiene-graft-polyamide, PB-g-PA6) with a low molecular weight trunk chain (PB) is obtained from the reaction between the maleic anhydride group of free or non-grafted PB-g-MAH and the amino group on PA6 molecules; while Copolymer I (LLDPE-g-PB-g-PA6) is obtained via the reaction between the maleic anhydride group of the grafted PB-g-MAH (i.e., LLDPE-g-PB-g-MAH) and the amino group of PA6. Copolymer I with a high molecular weight trunk chain, LLDPE, should strengthen the interface and favor stress transfer, enabling the deformation of PA6; and Copolymer II (PB-g-PA6) with a low molecular weight trunk chain, PB, facilitates the formation of a flat interface between LLDPE and PA6, thus promoting an elongated PA6 phase. Therefore, co-continuous morphology of LLDPE/PA6 blend is successfully prepared with only 25 wt% PA6 by controlling suitable amounts of Copolymers I and II in the blend.     

Studies on Linear Low-Density Polyethylene Functionalized by Ultraviolet Irradiation and Its Compatibilization

Summary Some groups containing oxygen such as C-O, C-OH and C=O were introduced onto the molecular chains of linear low-density polyethylene (LLDPE) through ultraviolet irradiation in air. The concentration of these groups containing oxygen increased with increasing irradiation time. After irradiation, the molecular weight of the LLDPE decreased, and its distribution widened. It was found that the gelation occurred after the LLDPE was irradiated for 12 h, and the gel content increased with increasing irradiation time. The crystal shape and space of the crystalline plane for irradiated LLDPE remained. Compared with those of LLDPE, the melt flow index, tensile strength and elongation at break of the irradiated LLDPE decreased, but its hydrophilicity increased and its toughness retained good. The polyamide 66 (PA66)/LLDPE/irradiated LLDPE blends were prepared by blending a small percentage of irradiated LLDPE with PA66. The melting temperature and crystallinity of both the LLDPE and PA66 components in the blends decreased with increasing irradiation time. The compatibility, dispersion and interfacial interaction between PA66 and LLDPE were improved after blending. With the addition of 5% LLDPE irradiated for 36 h, the tensile strength, bending strength and notched impact strength of the blends was enhanced from 48.3 MPa, 64.8 MPa and 30.8 J/m to 57.4 MPa, 71.5 MPa and 101.2 J/m, respectively.     

A study of LLDPE functionalized through ultraviolet irradiation and interfacial interaction of PA66/functionalized LLDPE blends

Some oxygen‐containing groups, such as C? O? C, C? OH, C?O, C(?O)O, and C(?O)OH, were introduced onto linear low‐density polyethylene (LLDPE) chains during ultraviolet irradiation under air, without adding any monomers and auxiliaries and without environmental pollution. After ultraviolet irradiation, the molecular weight of LLDPE decreased and its distribution became wider. The melting temperature and crystallinity of irradiated LLDPE decreased with irradiation time. The copolymer LLDPE‐g‐PA66 was formed by reaction between oxygen‐containing groups of irradiated LLDPE and amine or carboxyl end groups and amide linkage of polyamide 66 (PA66) during preparation of PA66/irradiated LLDPE blends. Compared with PA66/LLDPE blend, the mechanical properties of PA66/irradiated LLDPE blends were improved greatly because of the improved interface interaction and dispersion. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

PP—g —HMA增容尼龙6／聚丙烯共混物结构与性能研究

采用固相力化学方法制备的聚丙烯接枝羟甲基丙烯酰胺作增容剂,制备了尼龙6／聚丙烯共混物,通过SEM、DSC、流变性能测试和力学性能测试研究了共混物的结构、流变性能和力学性能。 结果表明,当尼龙6体积分数为80％时,增容共混体系中冲击强度出现峰值,达到77J／m,分散相尺寸变小,增容共混体系熔融粘度增加。通过Molau实验和FT－IR分析对增容机理作了初步探讨。     

Rheological aspects and film processability of poly (lactic acid)/linear low-density polyethylene blends

Poly (lactic acid) (PLA) and Linear low-density polyethylene (LLDPE) were compounded in a corotating twin screw extruder. PE-g-glycidyl methacrylate was also added as a reactive compatibilizer in PLA/LLDPE blend system, which lowered interfacial tension between PLA and LLDPE. Blown films were prepared by using a single-screw extruder for all compounded blends. The investigation of the rheological properties of a polymeric system is very important to study the processability and understand structure-property relationship in blown films. In the present research work, the rheological properties have been investigated to assess the processability of blown films of PLA/LLDPE blends. Oscillatory shear rheology viscoelastic spectra showed an increase in the storage and loss moduli with the increase in LLDPE and compatibilizer content, which indicated pronounced viscoelastic behavior of PLA with the addition of LLDPE and compatibilizer. A steady increase in the value of extensional viscosity as a function of time was observed with the addition of LLDPE and compatibilizer in PLA. The blends with higher LLDPE content exhibited much more prominent strain hardening characteristics than those with lower LLDPE content.     

Fusion bonding of maleated polyethylene blends to polyamide 6

Blends of linear low-density polyethylene (LLDPE) and linear low-density polyethylene–grafted maleic anhydride (LLDPE-gMA) were used to promote the adhesion to polyamide 6 (PA) in a three-layer coextruded film without using an additional adhesive or tie layer. The effect of bonding time and molecular weight (MW) of different maleated polyethylenes on the peel strength of the joints was analyzed. Direct evidence of a copolymer formed in-situ at the interfaces is also considered. The peel strength of fusion bonded layers of LLDPE/LLDPE-gMA blends with PA strongly depends on bonding time and molecular weight of the maleated polymer. Tensile properties of three-layer films, made up of PA as the central layer and LLDPE/LLDPE-gMA blends as the two external layers, are improved with increases in the maleic anhydride (MA) content in the blend. The in-situ formation of a copolymer between the MA in the blend and the terminal amine groups of the PA was confirmed by the Molau test, infrared (IR) spectroscopy, and thermal analysis (DSC).     

Investigation on the correlation between rheology and morphology of PA6/ABS blends using ethylene acrylate terpolymer as compatibilizer

Phase morphology and rheological behavior of polyamide 6 (PA6)/acrylonitrile butadiene styrene (ABS) polymers blends was studied using scanning electron microscopy and rheometry. The results showed that the phase morphology and rheological properties depends on blend composition. We evaluated the effect of addition of ABS as dispersed phase and EnBACO‐MAH (ethylene n‐butyl acrylate carbon monoxide maleic anhydride) as a compatibilizer on the morphological and rheological behaviors of PA6/ABS blends. It was concluded that there is a good agreement between the results obtained from rheological and morphological studies. As a consequence, addition of the ABS and compatibilizer weight percent led to a significant change in morphological structure and a great mounting in the viscosity as well as the elasticity. The rheological properties results demonstrate that adding compatibilizer to polymer blends led to increasing the crossover point, which shows a transition from a high viscous to a considerably more elastic behavior. Also, the slow transition of relaxation time peak from the peak of the PA6 to the peak of the ABS implies increasing the miscibility of the PA6/ABS blend components by increasing compatibilizer content. In addition, the Carreau–Yasuda model was used to extract information on rheological properties (zero shear viscosity and relaxation time) for PA6/ABS/EnBACO‐MAH blends by fitting the experimental data with this model. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011