等规聚丙烯离聚体增容聚丙烯/尼龙11共混体系研究

以碘代等规聚丙烯为大分子反应中间体,通过季胺化亲核取代反应和点击化学反应,制备了N-甲基咪唑聚丙烯离聚体(IA)和邻巯基苯胺盐酸盐聚丙烯离聚体(IB),并将其作为等规聚丙烯/生物基尼龙11 (i PP/PA11)共混体系的增容剂.通过动态力学分析(DMA)、扫描电镜(SEM)和力学性能测试,对i PP/PA11/聚丙烯离聚体三元共混体系的相形态与性能进行了系统研究. DMA测试结果显示,2种聚丙烯离聚体使i PP/PA11共混体系的玻璃化转变温度Tg相互靠近;SEM结果显示,离聚体的加入使分散相粒子尺寸显著减小,两相界面作用力增加;力学性能测试表明,i PP/PA11/IA、i PP/PA11/IB三元共混体系的拉伸强度和冲击强度保持较好的水平.以上研究结果表明,IA和IB均可以显著改善i PP/PA11共混体系的相容性.     

磨盘碾磨制备PA6/PP/SBS共混物的结构与性能

采用磨盘形力化学反应器,在室温下制备了PA6/PP超细混合粉体,与SBS共混制得PA6/PP/SBS共混物,测定了材料的力学性能并用TEM研究了材料在不同加工温度下相结构的变化.结果表明,通过固相力化学粉碎制备的PA6/PP混合微粉,改善了PA6与PP和SBS的相容性,促进了PA6及PP的分散和与SBS的相界面结合.在微粉填充量为4%～8%(质量分数)时,材料的拉伸强度大幅度提高,扯断伸长率保持不变.加工温度变化引起材料相结构的变化对材料性能产生显著影响.在PP熔融温度下加工,PP粒子产生粘连形成链状结构,可提高材料的力学性能.     

PP/PP-g-MAH/PA6共混物结构与可纺性研究

运用DSC、SEM、纺丝成形等手段研究了增容剂聚丙烯接枝马来酸酐 (PP g MAH)对聚丙烯 聚酰胺 6(PP PA6 )共混物结构和性能的影响 .结果表明 ,共混物呈典型海岛型两相结构 ;增容剂PP g MAH与PA6之间的在位反应改善了PP PA6共混体系的相容性 ,使共混物中PA6的热结晶峰消失 ,PP的结晶生长速率和成核速率降低 ,可纺性提高     

PA6/HIPS/PP-g-(GMA-co-St)反应共混体系的研究

通过扫描电镜、热分析、熔体流动速率、熔融扭矩和力学性能等测试方法研究了甲基丙烯酸缩水甘油酯(GMA)和苯乙烯(St)多单体熔融接枝聚丙烯[PP-g-(GMA-co-St)]对PA6/HIPS共混物的熔融流变性能、结晶行为、相形态和力学性能的影响.结果表明,在熔融共混过程中,PP-g-(GMA-co-St)中的环氧基与PA6的端氨基原位生成的接枝共聚物有效地降低了共混物的界面张力,提高了共混物的界面粘着力,使共聚物的流动速率降低,熔融扭矩提高;PA6分子链的规整性降低,结晶完善性变差.在PP-g-(GMA-co-St)的质量分数为10%时,共混物分散相的尺寸明显减少,力学性能得到较大提高;其中冲击强度超过纯PA6,达到HIPS水平.通过反应共混,制备了力学性能均衡的PA6/HIPS/PP-g-(GMA-co-St)共混物合金.     

炭黑填充聚丙烯/尼龙6/玻璃纤维复合材料的制备及表征

以聚丙烯(PP)和尼龙6(PA6)的共混物为基体材料,以导电炭黑(CB)和玻璃纤维(GF)作为填料,通过熔融共混的方法制备了导电复合材料。研究了GF和CB质量分数对复合材料热稳定性、导电性能、力学性能和微观形貌的影响。结果表明:CB粒子选择性分散在PA6中,同时PA6包覆在GF表面,通过具有较大长径比的纤维相互搭接形成连续的网络结构,从而显著降低复合材料的逾渗阈值。在相同CB质量分数下(2%),PP/PA6/GF/CB的表面电阻率相对于PP/PA6/CB体系降低了5个数量级。此外,引入GF后,材料的热稳定性和拉伸强度都有所提高。     

多组分单体接枝聚丙烯/尼龙6反应共混物结晶行为研究

用多组分熔融接枝的方法将甲基丙烯酸缩水甘油酯 (GMA)和苯乙烯 (St)共同接枝到聚丙烯 (PP)上 ,制得具有较高GMA接枝率的多单体接枝聚丙烯 ,PP g (GMA co St) .将PP g (GMA co St)与尼龙 6 (PA6 )进行共混 ,利用扫描电镜 (SEM) ,差示扫描量热计 (DSC)和广角X射线衍射 (WAXD)对共混物的形态和结晶进行了研究 .在共混过程中 ,PP g (GMA co St)与PA6反应原位生成了PP g PA6 ,有效改善了共混物的相容性 ,分散相尺寸明显减小 .在PP g (GMA co St) PA6为 3 7的体系中 ,PP g (GMA co St)出现分级结晶现象 ,其在较低温度下的结晶属于均相成核结晶 .在PP g (GMA co St) PA6为 7 3的体系中 ,由于PA6相分散细微 ,在通常结晶温度下不结晶 ,而是在低温下均相成核与PP g (GMA co St)同时结晶 .WAXD证实体系中接枝PP ,PA6为分别结晶 ,无共晶或新的晶型产生     

超细聚酰胺6粒子增韧聚丙烯体系的研究

采用磨盘形力化学反应器室温下制备了聚丙烯 (PP) /聚酰胺 6 (PA6 )超细粉体 ,研究了其粒度、粒度分布及PA6超细粒子填充对PP力学性能的影响 .结果表明 ,磨盘形力化学反应器可有效实现PP/PA6的粉碎 ,所得粉体平均粒径达微米级 ,初级粒子尺寸甚至可达纳米级 ,粒度分布呈双峰分布状态 .在PA6和PP熔点之间的温度下加工可制得PA6超细粒于填充的PP/PA6共混体系 ,其力学性能明显好于PP/PA6简单共混体系 ,30 %PA6用量下 ,拉伸强度由 2 3 .2MPa提高至 2 9 3MPa ,Izod缺口冲击强度由 4.6 2kJ/m2 提高到6 .34kJ/m2 .形貌分析结果表明 ,由于基本保持了PA6超细粉体的原始尺寸 ,填充体系中PA6相区尺寸小、分布均匀 ,与使用增容剂得到的相区结构类似 .     

剪切作用下马来酸酐接枝乙烯-辛烯共聚物和乙烯-丙烯酸丁酯-甲基丙烯酸缩水甘油酯共聚物对PA1010/PP共混物的增容作用比较

采用熔体共混的方法制备了两种增容剂增容的聚酰胺1010/聚丙烯(PA1010/PP)共混物,通过扫描电镜(SEM)、力学性能和差示扫描量热(DSC)测试,对动态保压注射成型(动态)和普通注射成型(静态)中增容剂POE-g-MAH(马来酸酐接枝乙烯-辛烯共聚物)和PTW(乙烯-丙烯酸丁酯-甲基丙烯酸缩水甘油酯共聚物)对PA1010/PP共混物的增容作用进行了比较研究.研究结果表明,普通注射成型中,PTW增容体系具有更小的分散相粒子,在DSC测试中出现两个结晶峰,即出现异相成核结晶和均相成核结晶,具有更好的拉伸和冲击性能,增容作用更佳.动态保压注射成型中施加剪切可以提高所有共混物的拉伸强度、拉伸模量和缺口冲击强度,PTW和POE-g-MAH两种增容剂增容体系冲击性能相近,但POE-g-MAH增容体系的分散相相区尺寸减小明显、分布均匀性显著增加,材料冲击强度增加幅度更大,表明剪切更有利于POE-g-MAH增容作用的进行.两种增容剂增容作用的不同源于它们化学组成的不同引起的材料形态差别.     

氧化石墨烯增容尼龙6/聚苯乙烯共混体系的研究

氧化石墨烯(GO)亲水性的边缘和疏水性的中间片层使其具有两亲特性.利用GO的这种特性,将其加入尼龙6(PA6)/聚苯乙烯(PS)的共混体系,以提高PA6和PS的相容性.通过两步法制备了PA6/PS/GO共混物,研究了GO对PA6/PS共混材料结构形态与力学性能的影响,并对其增容机理进行了探讨.扫描电镜(SEM)结果表明,添加GO后,共混材料的分散相尺寸明显变小,分散更为均匀,少量的GO即可达到良好的增容效果.动态力学性能(DMA)测试进一步证明了GO对PA6/PS共混物具有一定的增容性.理论计算也表明PS/GO共混物和PA6具有更接近的表面自由能和较低的界面自由能.添加GO后共混物材料的拉伸性能和韧性明显提高.GO添加量为0.1 wt％时,共混材料的断裂伸长率较未添加GO的共混材料提高了170％,断裂能也提高了近240％.     

剪切作用下PA1010/PP共混物的形态与性能研究

通过动态保压注射成型方法制备了聚酰胺1010/聚丙烯(PA1010/PP)共混物,并研究了形态与性能的关系.力学性能测试结果表明在熔体冷却过程中施加剪切可以大大提高共混物的拉伸强度、拉伸模量和缺口冲击强度,当PP的质量分数为20%时,共混物的缺口冲击强度达到21.3kJ/m2,是静态样的3倍多,拉伸强度达到50.9MPa,是静态样的1.5倍.扫描电镜(SEM)结果表明在动态保压样的横断面可以观察到剪切诱导的形态,中间是芯层,围绕着芯层的是剪切层,最外面是皮层,相区尺寸显著减小、分散相分散更趋均匀,特别是PP的质量分数为20%时,相区尺寸从原来的约3.9μm降低到约1.4μm.动态保压样机械性能的提高归因于剪切作用下独特相形态的形成,分子链沿流动方向的取向是拉伸强度提高的主要原因,而剪切使分散相颗粒变小和剪切层中分子链的取向是冲击强度提高的主要原因.     

Maleic Anhydride Polyethylene Octene Elastomer Toughened Polyamide 6/Polypropylene Nanocomposites: Mechanical and Morphological Properties

A series of polyamide 6/polypropylene (PA6/PP) blends and nanocomposites containing 4 wt% of organophilic modified montmorillonite (MMT) were designed and prepared by melt compounding followed by injection molding. Maleic anhydride polyethylene octene elastomer (POEgMAH) was used as impact modifier as well as compatibilizer in the blend system. Three weight ratios of PA6/PP blends were prepared i.e. 80:20, 70:30, and 60:40. The mechanical properties of PA6/PP blends and nanocomposite were studied through flexural and impact properties. Scanning electron microscopy (SEM) was used to study the microstructure. The incorporation of 10 wt% POEgMAH into PA6/PP blends significantly increased the toughness with a corresponding reduction in strength and stiffness. However, on further addition of 4 wt% organoclay, the strength and modulus increased but with a sacrifice in impact strength. It was also found that the mechanical properties are a function of blend ratio with 70:30 PA6/PP having the highest impact strength, both for blends and nanocomposites. The morphological study revealed that within the blend ratio studied, the higher the PA6 content, the finer were the POEgMAH particles.     

Effect of Silane Coupling Agent and Compatibilizer on Properties of Short Rossells Fiber/Poly(propylene) Composites

Rossells fiber reinforced polypropylene composites were prepared by melt mixing. The fiber content was 20 wt%. Octadecyltrimethoxysilane (OTMS) and maleic anhydride grafted polypropylene (MAPP) were used to improve the adhesion between poly(propylene) (PP) and the fiber. The mechanical, rheological, and morphological properties, and heat distortion temperature (HDT) of the composites were investigated. Tensile strength, impact strength, flexural strength and HDT of MAPP modified PP composites increased with an increase in MAPP content. However, no remarkable effect of MAPP content on the Young's modulus of the composites was found. OTMS resulted in small decreases of tensile strength and Young's modulus, and increase in impact strength. Scanning electron micrographs revealed that MAPP enhanced surface adhesion between the fiber surface and PP matrix.     

Development of continuous process enabling nanofibrillation of pulp and melt compounding

Microfibrillated cellulose (MFC), a mechanically fibrillated pulp mostly consisting of nanofibrils, is a very attractive material because of its high elastic modulus and strength. Although much research has been done on composites of MFC and polypropylene (PP), it has been difficult to produce such composites at an industrial level because of the difficulties in using MFC in such composites are not only connected to the polarity (that can be improved with compatibilizers), but also with the challenge to make a homogeneous blend of the components, and also the low temperature stability of cellulose that could cause problems during processing. We developed a new processing method which enables continuous microfibrillation of pulp and its melt compounding with PP. Never-dried kraft pulp and powdered PP were used as raw materials to obtain MFC by kneading via a twin-screw extruder. Scanning electron microscopy showed nano to submicron wide fibers entangled in the powdered PP. MFC did not aggregate during the melt compounding process, during which the water content was evaporated. Maleic anhydride polypropylene (MAPP) was used as a compatibilizer to reinforce interfacial adhesion between the polar hydroxyl groups of MFC and non-polar PP. We investigated the effect of MAPP content on the mechanical properties of the composite, which were drastically improved by MAPP addition. Needle-leaf unbleached kraft pulp (NUKP)-derived MFC composites had better mechanical properties than needle-leaf bleached kraft pulp (NBKP)-derived MFC composites. Injection molded NUKP-derived MFC composites had good mechanical and thermal properties. The tensile modulus of 50 wt% MFC composite was two times, and the tensile strength 1.5 times higher than that of neat PP. The heat distortion temperature of 50 wt% MFC content composite under 1.82 MPa flexural load was increased by 53 °C, from 69 to 122 °C. This newly developed continuous process using powder resin has the potential for application at an industrial level.     

Microstructure and non-isothermal crystallization behavior of PP/PLA/clay hybrid nanocomposites

Journal of Thermal Analysis and Calorimetry - Various compositions of polypropylene (PP) and poly(lactic acid) (PLA) blends were prepared by one-step melt compounding in a twin-screw extruder. Two...     

The effect of compatibilizers on the crystallisation, melting and polymorphic composition of β-nucleated isotactic polypropylene and polyamide 6 blends

Non-compatibilized and compatibilized blends of isotactic polypropylene (iPP) and polyamide 6 (iPP/PA6) as well as their β-nucleated versions were prepared using maleic anhydride functionalized iPP (MAPP) with different anhydride contents as compatibilizer. Ca-suberate, a highly efficient and selective β-nucleating agent was added to the blends in order to promote the formation of the β-modification of iPP. The melting and crystallisation characteristics, as well as the polymorphic composition of the blends were studied by differential scanning calorimetry (DSC). The supermolecular and phase structure of the blends were studied by polarised light microscopy (PLM). iPP and PA6 form blends with heterogeneous phase structure; the PA6 component is dispersed in the iPP matrix in the concentration range studied. The compatibilizer promotes the dispersion of PA6 resulting in smaller particles than without MAPP. In the non-compatibilized β-nucleated blends, an iPP matrix consisting mainly of the α-modification was formed already at low PA6 content. On the contrary, predominantly β-iPP matrix developed in the presence of MAPP compatibilizers. The formation of α-iPP matrix in the absence of compatibilizer is related to the selective encapsulation of the nucleating agent in the polar PA6 phase. The influence of the blending technique on the polymorphic composition of the matrix supports the hypothesis of selective encapsulation. Compatibilizers, besides their traditional benefits assist the distribution of the β-nucleating agent between both phases of the blends and promote the formation of a matrix rich in β-iPP. In the presence of β-nucleating agent MAPP with low anhydride content and blends of iPP containing maleated polypropylene crystallise predominantly in the β-form.     

Novel high-strength,micro fibrillated cellulose-reinforced polypropylene composites using a cationic polymer as compatibilizer

Novel high-strength, micro-fibrillated cellulose (MFC)-reinforced polypropylene (PP) composites were prepared using maleic anhydride polypropylene (MAPP) and a cationic polymer having a primary amino group (CPPA) as coupling agents. Un-dried kraft pulp was micro-fibrillated into nano- to submicron-wide fibrils by kneading with powdered PP and the coupling agents via a twin-screw extruder. The composites were prepared by injection molding. The MFC-reinforced PP composites containing both coupling agents MAPP and CPPA (combination system) showed extremely high mechanical strength compared with the MFC-reinforced composite containing only MAPP. The tensile strength of a 30 wt% MFC-PP composite containing the combination system was 27 % higher than that of the composite containing only MAPP, and more than 60 % higher than that of neat PP. In addition, the heat distortion temperature, under a 1.82-MPa flexural load, of the composite with the combination system was 17 °C higher than that of the composite with MAPP only, and 34 °C higher than that of neat PP. The anisotropy of the modulus and strength in the injection-molded MFC composites was lower than that of glass fiber-reinforced PP.     

Effect of maleic anhydride-grafted ethylene-propylene rubber on the mechanical, rheological and morphological properties of organoclay reinforced polyamide 6/polypropylene nanocomposites

Polyamide 6/polypropylene (PA6/PP = 70/30 parts) blends containing 4 phr (parts per hundred resin) of organophilic modified montmorillonite (organoclay) were compatibilized with maleic anhydride-grafted ethylene-propylene rubber (EPRgMA). The blends were melt compounded in twin screw extruder followed by injection molding. The mechanical properties of PA6/PP nanocomposites were studied by tensile and flexural tests. The microstructure of the nanocomposite were assessed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The dynamic mechanical properties of the PA6/PP blend-based nanocomposites were analyzed by using a dynamic mechanical thermal analyzer (DMTA). The rheological properties were conducted from plate/plate rheometry via dynamic frequency sweep scans. The melt viscosity in a high shear rate region was performed by using a capillary rheometer. The strength and stiffness of the PA6/PP-based nanocomposites were improved significantly with the incorporation of EPRgMA. Adding EPRgMA to the PA6/PP blends resulted in a finer dispersion of the PP phase. TEM and XRD results revealed that the organoclay was dispersed more homogeneously in the presence of EPRgMA, however, mostly in the PA6 phase of the blends. DMTA results showed that EPRgMA worked as an effective compatibilizer. The storage (G′) and loss moduli (G″) assessed by plate/plate rheometry of PA6/PP blends increased with the incorporation of EPRgMA and organoclay. Furthermore, the apparent shear viscosity of the PA6/PP blend increased significantly for the EPRgMA compatibilized PA6/PP/organoclay nanocomposite. This was traced to the formation of an interphase between PA6 and PP (via PA6-g-EPR) and effective intercalation/exfoliation of the organoclay.     

Influence of SEBS-g-MA on morphology, mechanical, and thermal properties of PA6/PP/organoclay nanocomposites

Polyamide 6/polypropylene (PA6/PP = 70/30 parts) blends containing 4 phr (parts per hundred resin) of organically modified clay (organoclay) toughened with maleated styrene-ethylene-butylene-styrene (SEBS-g-MA) were prepared by melt compounding using co-rotating twin-screw extruder followed by injection molding. X-ray diffraction (XRD) and transmission electron microscope (TEM) were used to characterize the structure of the nanocomposites. The mechanical properties of the nanocomposites were determined by tensile, flexural, and notched Izod impact tests. The single edge notch three point bending test was used to evaluate the fracture toughness of SEBS-g-MA toughened PA6/PP nanocomposites. Thermal properties were studied by using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). XRD and TEM results indicated the formation of the exfoliated structure for the PA6/PP/organoclay nanocomposites with and without SEBS-g-MA. With the exception of stiffness and strength, the addition of SEBS-g-MA into the PA6/PP/organoclay nanocomposites increased ductility, impact strength and fracture toughness. The elongation at break and fracture toughness of PA6/PP blends and nanocomposites were increased with increasing the testing speed, whereas tensile strength was decreased. The increase in ductility and fracture toughness at high testing speed could be attributed to the thermal blunting mechanism in front of crack tip. DSC results revealed that the presence of SEBS-g-MA had negligible effect on the melting and crystallization behavior of the PA6/PP/organoclay nanocomposites. TGA results showed that the incorporation of SEBS-g-MA increased the thermal stability of the nanocomposite.     

Morphology of isotactic polypropylene-polyamide 66 blends and their mechanical properties

Compounds were prepared with isotactic polypropylene (iPP) matrix and recycled polyamide 66 fibres (PA66), which were obtained as soft waste in industrial production process. Blends with pristine PA66 pellets were prepared as comparison. The blends showed the presence of PA66 particles dispersed in the PP continuous phase. Considering the incompatibility of the two polymers the addition of isotactic polypropylene grafted with maleic anhydride (iPPgMA) as compatibilizer was investigated: the blends were characterized by thermal, mechanical, dynamic-mechanical and morphological analyses. The presence of the compatibilizer significantly influences the morphology of the blends, inducing a finer dispersion and promoting interfacial adhesion. The characterization of pristine and recycled PA66 did not show a meaningful difference in the value of molecular weight, on the other hand marked differences were presented in the flexural moduli of the two materials; analogous differences were exhibited by the blends: compounds prepared with recycled PA66 showed flexural moduli higher than compatibilized blends with pristine PA66.     

动态固化聚丙烯/环氧树脂共混物的研究

将动态硫化技术应用于热塑性树脂 热固性树脂体系 ,制备了动态固化聚丙烯 (PP) 环氧树脂共混物 .研究了动态固化PP 环氧树脂共混物中两组分的相容性、力学性能、热性能和动态力学性能 .实验结果表明 ,马来酸酐接枝的聚丙烯 (PP g MAH)作为PP和环氧树脂体系的增容剂 ,使分散相环氧树脂颗粒变细 ,增加了两组分的界面作用力 ,改善了共混物的力学性能 .与PP相比 ,动态固化PP 环氧树脂共混物具有较高的强度和模量 ,含 5 %环氧树脂的共混物拉伸强度和弯曲模量分别提高了 30 %和 5 0 % ,冲击强度增加了 15 % ,但断裂伸长率却明显降低 .继续增加环氧树脂的含量 ,共混物的拉伸强度和弯曲模量增加缓慢 ,冲击强度无明显变化 ,断裂伸长率进一步降低 .动态力学性能分析 (DMTA)表明动态固化PP 环氧树脂共混物是两相结构 ,具有较高的储能模量 (E′)