HDPE-g-GMA对PA6/UHMWPE共混物性能的影响

采用自制甲基丙烯酸缩水甘油酯接枝高密度聚乙烯(HDPE-g-GMA)作为增容剂来增容尼龙6/超高分子量聚乙烯(PA6/UHMWPE)共混物。通过Molau试验、红外光谱分析、扫描电子显微镜观察和物理力学性能测试,研究了HDPE-g-GMA在熔融共混过程中对PA6/UHMWPE共混物的增容作用。结果表明,HDPE-g-GMA与PA6发生化学反应所生成的接枝聚合物对PA6/UHMWPE共混物有较好的增容作用;PA6/UHMWPE共混物的界面形态和力学性能均有较大改善．吸水率也有所降低。     

相容剂对CF/PA6共混物结构与性能的影响

通过挤出共混法制备了CF/PA6/PP-g-MAH和CF/PA6/SMA复合材料。采用SEM、DSC、DMA及力学性能测试,研究了PP-g-MAH和SMA对CF/PA6(5/95)共混物的微观形态、结晶行为及力学性能的影响。结果表明:2种相容剂对CF/PA6共混物都有明显的增容作用,其中SMA的增容效果较好;共混物的拉伸强度、冲击强度、弯曲性能及储存模量显著提高,玻璃化转变温度向高温区移动;SMA和PP-g-MAH均能促进CF对PA6基体的异相成核作用。     

PPO-g-MA对PPO/PA66共混物的原位增容作用

用傅里叶变换红外光谱证明了聚(2,6-二甲基-1,4-苯醚)(PPO)与马来酸酐(MA)在过氧化二异丙苯的作用下,采用熔融挤出法生成了PPO-g-MA。通过透射电子显微镜、扫描电子显微镜、Instron毛细管流变仪、力学性能试验机和Molau实验分别对不同PPO-g-MA用量的PPO/聚酰胺66(PA66)共混物的亚微相态、流变行为、力学性能进行了考察,结果表明,PPO-g-MA对PPO/PA66共混物起到了原位增容作用。     

微纳叠层制备HDPE/PA6原位成纤复合材料的形态及性能

采用微纳叠层共挤制备了高密度聚乙烯(HDPE)/聚酰胺6(PA6)原位成纤增强复合材料,通过扫描电子显微镜(SEM)分析了普通共混挤出和微纳叠层挤出共混物中分散相PA6的形态及分布;利用差示扫描量热仪(DSC)分析研究了复合体系中PA6对HDPE基体熔点和结晶性能的影响;讨论了两种加工方式条件下PA6添加量对复合材料静态力学性能的影响以及加工方式对复合体系力学性能的作用。结果表明:在微纳叠层挤出共混物HDPE/PA6(质量比85/15)中存在直径约为3μm的纤维;随着PA6含量的增加,复合体系的结晶度增大。     

EBA-g-MAH共聚物增容PA6/ABS共混体系的聚集态结构与性能

通过熔融共混法制备了EBA-g-MAH增容PA6/ABS共混物,采用FTIR、SEM、DSC等测试了EBA-g-MAH对PA6/ABS共混物的增容作用;并讨论了EBA-g-MAH对PA6/ABS共混物的结晶性、力学性能及吸水率的影响。研究结果表明:EBA-g-MAH与PA6发生化学反应所生成的接枝物对PA6/ABS共混物有较好的增容作用,使分散相尺寸明显减小;PA6/ABS共混物的冲击强度得到很大的提高,比纯PA6提高430%,吸水性也得到改善,但是拉伸强度有所降低。DSC研究表明:EBA-g-MAH的加入抑制了PA6/ABS共混物中PA6的结晶,使PA6结晶度降低。     

原位增容PA6/PE-HD共混物的非等温结晶动力学研究

利用差示扫描量热仪研究了原位增容的聚酰胺6/高密度聚乙烯（PA6/PE-HD）共混物的非等温结晶过程,用经Jeziorny 修正的Avrami方程和Mo法对其非等温结晶动力学进行了研究,计算并得到非等温结晶动力学参数。结果表明,该方程和方法适合于处理纯PA和PA6/PE-HD共混物的非等温结晶过程;在PA6/PE-HD共混物非等温结晶过程中, 在其初期结晶阶段可能同时包含了均相成核和异相成核, 在二次结晶阶段结晶生长可能是一维生长,并且PE-HD的加入,起到异相成核的作用,促进了晶核的生长。此外, 还利用Vyazovkin的方法求出PA6/PE-HD共混物结晶活化能与温度之间的关系。     

不同增容剂对PA6/PE-HD共混物性能的影响

制备了3种增容剂增容的尼龙(PA6)/高密度聚乙烯(PE-HD)共混物,对其力学性能、吸水性、表面疏水性进行了测试,用体视显微镜对共混物拉伸断面和冲击断面进行观察。结果表明,HD800E增容的PA6/PE-HD力学性能较好,特别是其断裂伸长率和冲击强度较大,相对于纯PA6,分别提高105.3%和36.9%,3种增容剂均能改善PA6的吸水性能和表面疏水性,其中,HD800E增容的PA6/PE-HD的饱和吸水率较小,为纯PA6的46.2%。     

原位增容PA6/PE-HD共混物的等温结晶动力学研究

采用差示扫描量热仪研究了原位增容聚酰胺6/高密度聚乙烯（PA6/PE-HD）共混物的等温结晶行为,采用Avrami方程分析了纯PA6和PA6/PE-HD共混物的等温结晶动力学,并通过Hoffman-Weeks方法计算出了共混物的平衡熔点。结果表明,二者的Avrami指数介于2.19~3.70之间,表明PA6晶体的生长方式为二维盘状生长和三维球晶生长并存,PE-HD的加入并没有影响PA6晶体的生长方式。偏光显微镜分析表明,纯PA6能够生成球晶,但加入PE-HD后,球晶尺寸明显变小,说明PE-HD的加入起到了异相成核的作用,加快了PA6的结晶过程。     

HDPE-g-GMA反应性增容PA66/UHMWPE共混合金性能研究

以甲基丙烯酸缩水甘油酯接枝高密度聚乙烯(HDPE-g-GMA)作为聚酰胺66/超高摩尔质量聚乙烯(PA66/UHMWPE)共混合金的增容剂,采用熔融法制备了PA66/uHMwPE/HDPE-g-GMA共混合金.通过Molau试验、SEM观察和力学性能测试,研究了HDPE-g-GMA在熔融共混过程中对PA66/UHMWPE共混合金的增容作用.结果表明:HDPE-g-GMA与PA66发生了化学反应,所生成的接枝共聚物对PA66/UHMWPE共混合金有较好的增容作用;PA66/UHMWPE共混合金的界面形态和力学性能均有较大改善,吸水率也有所降低.     

共混工艺对PA6/POE-g-MAH/CaCO3三元复合体系力学性能的影响

研究了4种不同共混工艺对PA6/POE-g-MAH/CaCO3三元复合体系韧性的影响。通过不同的加料顺序和挤出次数对PA6、POE-g-MAH、CaCO3进行熔融共混后挤出注塑,并对其进行力学性能测试和SEM观察。研究结果表明:形成"核壳"结构界面的材料的韧性最高。不同制备工艺下,POE-g-MAH/CaCO3先挤出,再与PA6挤出,注塑得到的共混物的冲击强度最高但弹性模量最低;PA6/CaCO3挤出,再与POE-g-MAH挤出,注塑得到的共混物韧性次之,但弹性模量最高;PA6/POE-g-MAH/CaCO3PP一起挤出,注塑得到的共混物韧性再次;PA6与POE-g-MAH挤出,再与CaCO3挤出,注塑得到的共混物韧性最差。     

（PE—HD／PE—LD）—g—GMA增容PC／PE—UHMW共混物的冲击性能与断面形态

采用反应挤出方法，制备了缺口冲击性能良好的(PE-HD／PE-LD)-g-GMA(甲基丙烯酸缩水甘油脂)增容PC／PE-UHMW共混物。当增容剂(PE-HD／PE-LD)-g-GMA用量为6份时，共混物的冲击强度达到最大值66kJ／m^2，比未增容PC／PE-UHMW提高了28．5kJ／m^2。冲击断面的SEM分析表明，增容剂的加入产生了反应性的增容效果，提高了两相之间的界面粘结力，促进了相的分散，对基体的剪切屈服形变有利，冲击性能得以改善。     

螺杆构型对反应挤出制备聚乙烯/聚酰胺6原位合金的影响

以己内酰胺（CL）、高密度聚乙烯(PE-HD)、马来酸酐接枝高密度聚乙烯（PE-HD-g-MAH）为主要原料,采用反应挤出法制备PE-HD /聚酰胺6（PA6）原位合金,研究螺杆构型对PE-HD/PA6原位合金制备的影响。研究发现,停留时间长的螺杆构型,其对应的原位合金中CL单体转化率较高;在3种螺杆构型中,带有大导程拉伸元件的螺杆,所制备的原位合金中分散相PA6的粒径最小,其原因在于CL单体在PE-HD中的初始分散状态对合金中分散相PA6的粒径有直接影响,而大导程拉伸元件更有利于CL在PE-HD基体中的破碎与分散。     

Compatibilization of polypropylene/nylon 6 blends with a polypropylene solid‐phase graft

The compatibilization of polypropylene (PP)/nylon 6 (PA6) blends with a new PP solid‐phase graft copolymer (gPP) was systematically studied. gPP improved the compatibility of PP/PA6 blends efficiently. Because of the reaction between the reactive groups of gPP and the NH₂ end groups of PA6, a PP‐g‐PA6 copolymer was formed as a compatibilizer in the vicinity of the interfaces during the melting extrusion of gPP and PA6. The tensile strength and impact strength of the compatibilized PP/PA6 blends obviously increased in comparison with those of the PP/PA6 mechanical blends, and the amount of gPP and the content of the third monomer during the preparation of gPP affected the mechanical properties of the compatibilized blends. Scanning electron microscopy and transmission electron microscopy indicated that the particle sizes of the dispersed phases of the compatibilized PP/PA6 blends became smaller and that the interfaces became more indistinct in comparison with the mechanical blends. The microcrystal size of PA6 and the crystallinity of the two components of the PP/PA6 blends decreased after compatibilization with gPP. The compatibilized PP/PA6 blends possessed higher pseudoplasticity, melt viscosity, and flow activation energy. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 420–427, 2004     

Ultrasonic treatment of polypropylene,polyamide 6, and their blends

The mechanical and rheological properties of polypropylene (PP), polyamide 6 (PA6), and their blends treated by high‐intensity ultrasound during extrusion were investigated. A lower head pressure was achieved in the extrusion of these thermoplastics. The mechanochemical and sonochemical effects of ultrasound led to simultaneous ionic condensation reactions and degradation in a homogeneous melt of PA6, with a prevailing effect of enhanced polycondensation reactions. The observed improvements in the mechanical properties of ultrasonically treated PA6 were attributed to condensation reactions, which yield a higher molecular weight, a higher crystallinity, and a more uniform crystal size distribution. At high ultrasound amplitudes, for PP, the degradation of polymer chains was observed with little deterioration of the mechanical properties. For ultrasonically treated PP/PA6 blends, a competition between the degradation and partial in situ compatibilization effect was found. At certain blend ratios, the tensile toughness and impact strength of the treated blends were almost double those of the untreated blends. However, full compatibilization was not achieved, possibly because of the low coupling selectivity of highly reactive radicals. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2643–2653, 2006     

HDPE-g-MAH和POE-g-MAH对HDPE/PA6共混物性能的影响

分别以高密度聚乙烯接枝马来酸酐（HDPE-g-MAH）和乙烯-辛烯共聚物接枝马来酸酐（POE-g-MAH）作为相容剂,通过熔融挤出法对PE100/PA6共混物进行共混改性。研究了两种相容剂的用量对共混物力学性能、热性能和微观结构的影响。结果表明：HDPE-g-MAH与POE-g-MAH相比,都使体系发生反应性增容的同时,对共混物的结晶性更为有利,使得PE100/PA6/HDPE-g-MAH的综合性能更好,更适合作为PE100耐热改性时的增容剂。     

Investigations on the formation of composites by injection molding of PA6 and different grafted polypropylenes and their blends

Blends of different types of polypropylenes (PP) with polyamide 6 (PA6) were produced by extrusion. The PPs used were a PP homopolymer, a maleic anhydride‐grafted homopolymer, and an acrylic acid‐grafted homopolymer. The blends were characterized by DSC measurements, selective extraction, infrared spectroscopy, REM microscopy, melt rheology, and their mechanical properties. Three types of interactions in the blends as well as in two‐component composites mold by the core‐back process could be identified. Blends of PP with PA6 were not compatible, and two‐component bars could not be produced. Blends of PPgAA and PA6 were made compatible during reactive extrusion. Two‐component bars could be produced only with a blend containing 50 wt % PA6. The composite formation was based on the interdiffusion of PA6 in both components and the reactive compatibilization in the blends. Blends of PPgMAn were also compatibilized during reactive extrusion. The composite formation on two‐component injection molding was based on two mechanisms: the interdiffusion at sites, where PA6 chains of both the components came into contact, and an interfacial reaction, where PPgMAn and PA6 came into contact. The interfacial reaction was supported by the high mobility of the first component at the temperature of the melt of the second component. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2992–2999, 2006     

Polymer blends of PA6 and PPE compatibilized by phenolic novolac epoxy coupler

A commercially available multi-functional epoxy monomer, phenolic novolac epoxy (PNE) resin, has demonstrated to be an effective reactive compatibilizer for the blends of polyamide-6 (PA6) and poly(2,6-dimethyl-1,4-phenylene ether) (PPE). It requires about 1/10 by weight relative to a typical conventional reactive compatibilizer to achieve same level of compatibilization in terms of mechanical property improvements. By acting as a coupler, this multi-functional epoxy can react with PA6 and PPE during melt blending and produces the desirable PA6-co-PNE-co-PPE mixed copolymers at the interface. This in situ-formed copolymer containing PA6 and PPE segments tends to reside at the interface between PA6 and PPE domains to reduce melt interfacial tension and enhance interface adhesion as an efficient compatibilizer of the PA6/PPE blends.     

Devolatilization: A critical sequential operation for in situ compatibilization of immiscible polymer blends by one-step reactive extrusion

The main objective of this study was to show that an efficient removal of residual monomers is very important for in situ compatibilization of immiscible polymer blends by one step reactive extrusion. One-step reactive extrusion means that when compatibilizing two immiscible polymers with one polymer containing potential functional groups and the other being chemically inert with respect to these functional groups, functionalization of the chemically inert polymer and its subsequent interfacial reaction with the functional polymer are accomplished in a single extrusion process. Two model blend systems were chosen: polypropylene/poly(butylene terephthalate) (PP/PBT) and high density polyethylene/polyamide 6 (HDPE/PA6). A co-rotating intermeshing twin screw extruder was used to process these blends. Glycidyl methacrylate (GMA) and maleic anhydride (MA) were used to functionalize PP and HDPE, respectively. Results showed that the mechanical properties of both blends in terms of elongation at break and impact strength were improved to a much greater extent with up-stream devolatilization compared with down-stream devolatilization.