增容聚丙烯/聚苯乙烯共混物的相形态

综述了作为增容剂的接枝共聚物与嵌段共聚物,反应增容,其他技术增容以及共混条件对聚丙烯／聚苯乙烯(PP,PS)共混物的相形态研究进展。PP／PS共混物通过增容可以改善共混物相形态和提高界面粘结,这为提高PP／PS共混物的物理与力学性能提供了依据。     

增容剂对PBT/PP共混物结构性能的影响

以乙烯/乙酸乙烯酯共聚物接枝马来酸酐(EVA-g-MAH)、乙烯/辛烯共聚物接枝马来酸酐(POE-g-MAH)为增容剂,采用熔融共混法制备了不同组成比例的PBT/PP共混物,通过DSC、TG、XRD、SEM等多种手段测试了共混物的性能,详细研究PBT/PP质量比、增容剂种类和用量对共混物结构性能的影响。结果表明:PBT/PP的质量比为70/30时,所得共混物的微观形貌最好;加入2种增容剂增容后发现,EVA-g-MAH对PBT/PP共混物相容性的改善效果比POE-g-MAH的增容效果好,并且PBT/PP/EVA-g-MAH的质量比为70/30/3时共混体系相容性最好。     

PP／PS增容研究进展

总结了PP／PS复合材料增容的主要方法,包括接枝共聚物增容、嵌段共聚物增容、原位增容、无机填料增容等,并对PP／PS增容复合材料的应用作出了展望。     

一种新型PP/PS增容剂的制备及性能

通过一种可溶性锌盐催化苯乙烯和丙烯腈共聚物将睛基基团转换为(噁)唑啉基团的方法来合成一种新型活性聚合物PP/PS增容剂(OX-SAN).用1H-NMR和FTIR对增容剂(OX-SAN)进行了表征.用扫描电子显微镜(SEM)观察了OX-SAN/MPP/PA6混合物的断裂面形貌.并对OX-SAN/MPP/PA6三元混合物作为PP/PS共混增容剂的增容效果进行了研究.结果表明:OX-SAN/MPP/PA6三元混合物对PP/PS起到增容作用,并且使PP/PS力学性能得到提高.     

长支链聚丙烯增容聚丙烯共混物的研究

以聚丙烯（PP）为原料,通过熔融接枝法制备长支链聚丙烯（LCBPP）,将LCBPP分别加入到PP／聚苯乙烯（PS）、PP／苯乙烯-丙烯腈嵌段共聚物（SAN）和PP／聚对苯二甲酸乙二醇酯（PET）共混体系里。采用傅里叶变换红外（FTIR）和拉伸流变仪对LCBPP进行表征。采用扫描电子显微镜对共混物的断面进行观察。结果表明,LCBPP对分散相具有一定极性的体系表现出良好的增容效果;在组分比为70/30的PP/SAN 和PP/PET体系中加入５％的LCBPP后,体系分散相尺寸明显细化且分散均匀,但是其增容效果没有枝马来酸酐接聚丙烯（PP-g-MAH）的增容效果明显;LCBPP对于PP/PS体系的相容性有轻微的改善。     

关于PS/PP系共混物的研究——第1报 PS/PP共混体系的相容性和相态结构

本研究以苯乙烯—乙烯—丁烯—苯乙烯嵌段共聚物(SEBS)和苯乙烯—乙烯—丙烯嵌段共聚物(SEP)为界面活性剂(相溶化剂),研究聚苯乙烯等规聚丙烯(PS/PP)共混体系的相容性;研究PS/PP两成分体系和添加界面活性剂后三成分体系的相态结构及相界面形态。为制取结构稳定的PS/PP系共混物,进一步制取具有特殊性能约PS/PP共混纤维提供实用的工艺条件和理论依据。     

PP接枝聚合物对PP/PS共混物相形态的影响

通过原子转移自由基反应合成了聚丙烯(PP)接枝聚苯乙烯(PS) (PP-g-PS),研究了PP-g-PS对PP/PS共混物相形态的影响.采用扫描电子显微镜、偏光显微镜观察了共混物的断面形貌和等温结晶形态.结果表明: 加入PP-g-PS对PP/PS共混物起到了良好的增容作用,表现在两相界面模糊,分散相尺寸减小.当PP-g-PS中x(PS)为5.10% 左右时即可起到增容改善相界面的作用.相容性的提高改善了PP/PS共混物的发泡性能.     

橡胶-塑料共混体高温热塑性弹性体:技术发展水平综述(2)

正6基于高性能耐热性橡胶的高温TPE和TPV以下将讨论几种高温TPE(以耐热性橡胶为基础),主要讨论其制备方法、几种性能和形态。6.1 PP/丁腈橡胶TPE Coran等人通过动态硫化由PP/NBR复合材料(Geolast)开发了耐油TPE。他们用酚醛树脂硫化剂对共混组分进行工艺增容。发现生成了原位接枝共聚物。这种反应的可能示意图见图17。相比未硫化共混体,工艺增容共混体的力学性能显著改善。增容PP/NBR共混体的耐热油性非常优异。然而,这些共混体的低温性能差。     

混合增容剂对HDPE/sPS共混物形态及性能的影响

分别采用2种组成相近而分子量不同的苯乙烯-乙烯/丁烯-苯乙烯共聚物(SEBS)以及两者的混合物对高密度聚乙烯/间规聚苯乙烯(HDPE/s PS)共混物进行增容改性。通过扫描电镜(SEM)及拉伸实验试验考查了增容剂的分子量及含量对HDPE/s PS共混物形态结构及力学性能的影响。结果表明:两种增容剂都能降低s PS分散相尺寸,使两相界面的粘合力增强。相对较低分子量的SEBS(K1652)能显著提高两相界面粘结性,进而能有效提高共混物的拉伸强度,而较高分子量的SEBS(K1651)能显著改善共混物的韧性。一定比例混合的共聚物作为增容剂在改善共混物性能方面具有协同效应,可以同时提高共混物拉伸强和断裂伸长率,混合增容剂效果优于单一增容剂。HDPE/s PS共混物中加入质量分数4%的K1652和2%的K1651,共混物的综合力学性能最优。     

Nano-CaCO3/PP/PS复合材料的热降解行为的研究

用密炼机制备了马来酸酐接枝PP(MPP)和丙烯酸接枝PP(FPP)增容的nano-CaCO3/PP/PS复合材料,用TGA研究复合材料的热降解行为。结果表明:加入nano-CaCO3有助于提高PP/PS共混物的热稳定性,对于提高复合材料的热稳定性,FPP、MPP与nano-CaCO3不存在协同作用;nano-CaCO3/增容PP/PS共混物复合材料的DTG曲线在400℃~500℃间有两个失重速率峰,分别对应PS和PP的热降解。     

Compatibilization by main‐chain thermotropic liquid crystalline ionomer of blends of PBT/PP

The miscibility and mechanical properties of the blends of polybutylene terephthalate (PBT) and polypropylene (PP) with a liquid crystalline ionomer (LCI) containing a sulfonate group on the terminal unit as a compatibilizer were assessed. SEM and optical microscopy (POM) were used to examine the morphology of blends of PBT/PP compatibilized by LCI. DSC and TGA were used to discuss the thermal properties of PBT/PP blends with LCI and without LCI. The experimental results revealed that the LCI component affect, to a great extent, the miscibility and crystallization process and mechanical property of PBT/PP blends. The fact is that increasing LCI did improve miscibility of PBT/PP blends and the addition of 1% LCI to the PBT/PP blends increased the ultimate tensile strength and the ultimate elongation. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1110–1117, 2002     

Studies on morphology,mechanical, thermal,and dynamic mechanical behavior of extrusion blended polypropylene and thermotropic liquid crystalline polymer in presence of compatibilizer

Polypropylene was melt blended in a single screw extruder with thermo tropic Vectra B‐950 liquid crystalline polymer (copolyester amide) in different proportions in presence of 2% of EAA, ethylene‐acrylic acid copolymer (based on PP) as a compatibilizer. The mechanical properties of such compatibilized blends were evaluated and compared in respect of their Young's Modulii, Ultimate tensile strength, percent elongation at break, and toughness to those of Pure PP. The Morphology was studied by using a polarizing light microscope (PLM) and Scanning electron microscope (SEM). The Thermal characterization of these blends were carried out by differential scanning calorimeter (DSC).The mechanical properties under dynamic conditions of such compatibilized blends and pure PP were studied by dynamic mechanical analyzer (DMA). Mechanical analysis (Tensile properties) of the compatibilized blends displayed improvements in Modulii and ultimate tensile strength (UTS) of PP matrix with the incorporation of 2–10% of LCP incorporation. The development of fine fibrillar morphology in the compatibilized PP/LCP blends had large influence on the mechanical properties. Differential scanning calorimeter (DSC) studies indicated no remarkable changes in the crystalline melting temperature of the blends with respect to that of pure PP. However, an increase in the softening range of the blends over that of PP was observed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Crystallization behavior and mechanical properties of polypropylene random copolymer/poly(ethylene‐octene) blends

New polymer blends of polypropylene random copolymer (PP‐R) and poly(ethylene‐octene) (POE) were prepared by melt‐blending process using a corotating twin‐screw extruder. The POE content was varied up to 35%. The toughening efficiency of POE for PP‐R was evaluated by the mechanical properties of the resulted PP‐R/POE blends. The crystallization behavior and morphology of the blends were also studied. Results show that POE acts as nucleation agent to induce the crystallization of PP‐R matrix at higher crystallization temperature. Super‐toughened PP‐R/POE blends (Izod impact strength more than 500 J/m) can be readily achieved with only 10 wt % of POE. The high toughness of PP‐R/POE is attributed to cavitation and shear yielding of matrix PP‐R, as revealed by the morphology studies. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Phase morphology of PP/COC blends

Phase morphology of polymer blends PP/COC, where PP is polypropylene and COC is a copolymer of ethene and norbornene, was characterized by means of scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM). PP/COC blends were prepared by injection molding and their morphology was studied for six different compositions (90/10, 80/20, 70/30, 60/40, 50/50, and 25/75 wt %). The intention was to improve PP properties by forming COC cocontinuous phase, which should impart to the PP matrix higher stiffness, yield stress, and barrier properties. Surprisingly enough, all studied blends were found to have fibrillar morphology. In the 90/10, 80/20, and 70/30 blends, the PP matrix contained fibers of COC, whose average diameter increased with increasing COC fraction. In the 60/40 blend, the COC component formed in the PP matrix both fibers and larger elongated entities with PP fibers inside. The 50/50 blend was formed by COC cocontinuous phase with PP fibers and PP cocontinuous phase with COC fibers. In the 25/75 blend, PP fibers were embedded in the COC matrix. In all blends, the fibers had an aspect ratio at least 20, were oriented in the injection direction, and acted as a reinforcing component, which was proven by stress–strain and creep measurements. According to the available literature, the fibrous morphology formed spontaneously in PP/COC is not common in polymer blends. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 253–259, 2004     

Rheology and impact characteristics of compatibilized polypropylene-liquid crystalline polymer composites

Polypropylene-liquid crystalline polymer (PP/LCP) and maleic anhydride compatibilized PP/LCP blends were prepared using the extrusion technique followed by injection molding. The LCP employed was Vectra A950 which consists of 25 mol % of 2,6-hydroxynaphthoic acid and 75 mol % of p-hydroxybenzoic acid. The rheology, morphology, and impact behavior of compatibilized PP/LCP blends were investigated. The rheological measurements showed that the viscosity of LCP is significantly higher than that of the PP at 280°C. This implied that the viscosity ratio of the LCP to the polymer matrix is much larger than unity. Scanning electron microscopy (SEM) observations revealed that the LCP domains are dispersed mainly into elongated ellipsoids in the PP/LCP blends. However, fine fibrils with large aspect ratios were formed in the compatibilized PP/LCP blends containing LCP content ≥ 10 wt %. The development of fine fibrillar morphology in the compatibilized PP/LCP blends had a large influence on the mechanical properties. The Izod impact strength of the PP/LCP blends showed little dependence on the LCP concentrations. On the other hand, the impact strength of the compatibilized PP/LCP blends was dependent on the LCP concentrations. The correlation between the LCP fibrillar morphology and spherulitic structure with the impact properties of the compatibilized PP/LCP blends is discussed. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 521–530, 1998     

Effect of recycled polypropylene on polypropylene/high‐density polyethylene blends

The effect of recycled PP on incompatible blends of virgin polypropylene (PP) and high‐density polyethylene (HDPE) was studied. Recycled PP from urban solid waste was extracted with methyl ethyl ketone and the compatibilizing action of the product before and after extraction was examined. The characterization of the recycled PP was performed by FTIR, NMR, and DSC analyses. Mechanical properties of the blends were evaluated. The results showed partial compatibility of the blend components, reflected in the improvement of the tensile strength and elongation. Best results were achieved by the addition of extracted recycled PP on the 50/50 PP/HDPE blends. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1305–1311, 2001     

Processing‐improved properties and morphology of PP/COC blends

The aim of this study was to improve mechanical properties of polypropylene/cycloolefin copolymer (PP/COC) blends by processing‐induced formation of long COC fibers. According to the available literature, the fibrous morphology in PP/COC blends was observed just once by coincidence. For this reason, we focused our attention on finding processing conditions yielding PP/COC fibrous morphology in a well‐defined, reproducible way. A number of PP/COC blends were prepared by both compression molding and injection molding (IM). Neat polymers were characterized by rheological measurements, whereas phase morphology of the resulting PP/COC blends was characterized by means of scanning electron microscopy (SEM). The longest COC fibers were achieved in the injection molded PP/COC blends with compositions 75/25 and 70/30 wt %. Elastic modulus and yield strength of all blends were measured as functions of the blend composition using an Instron tensile tester; statistically significant improvement of the yield strength due to fibrous morphology was proved. Moreover, two different models were applied in the analysis of mechanical properties: (i) the equivalent box model for isotropic blends and (ii) the Halpin‐Tsai model for long fiber composites. In all PP/COC blends prepared by IM, the COC fibers were oriented in the processing direction, as documented by SEM micrographs, and acted as a reinforcing component, as evidenced by stress–strain measurements. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Polymer blends based on polyolefin elastomer and polypropylene

A new family of homogeneous polyolefin polymers that exhibit unique molecular and rheological properties designated polyolefin elastomers (POEs) are characterized by a narrow molecular weight and high degrees of comonomer distribution. Because these copolymers are often elastomeric in nature, one of the uses for these materials is as impact properties improver for brittle polymers such as polypropylene at low temperatures. In this work a study was carried out about the effectiveness of the polyethylene elastomer (POE) as an impact modifier for polypropylene in relation to the traditional modifier EPDM. In this study the flow properties of of the POE/PP and EPDM/PP blends were also evaluated. The blends were analyzed by solid-state ¹³C nuclear magnetic resonance (¹³C-NMR) spectroscopy, scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). The results showed that PEE/PP and EPDM/PP blends present a similar crystalline behavior, which resulted in a similar mechanical performance of the blends, on the composition analyzed. It was also verified that the POE/PP blend presents lower torque values than the EPDM/PP blend, which indicates a better processability when POE is used as an impact modifier. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 2005–2014, 1997     

Blends of styrene–butadiene–styrene triblock copolymer and isotactic polypropylene: morphology and thermomechanical properties

A set of blends of styrene–butadiene–styrene triblock copolymer (SBS) and isotactic polypropylene (i‐PP) in a composition range 0–100 % polypropylene by weight was prepared in a twin screw extruder. The morphology of the blends has been studied by transmission electron microscopy. The blends present phase separation. Dynamic mechanical measurements show an improvement of the mechanical properties of SBS when i‐PP is the dispersed phase. This reinforcing effect can be observed even at high temperatures when i‐PP is in the rubbery state. The mechanical properties of the blends have been interpreted using Takayanagi's block model. The melting and crystallization behaviour of the i‐PP in the blends has been studied by differential scanning calorimetry. The fractionated crystallization phenomenon has been observed in the blends where i‐PP forms the dispersed phase. The results are consistent with the morphology shown by the blends, in particular, with its phase inversion, which occurs at a composition near to 50% i‐PP. © 2000 Society of Chemical Industry     

热致性液晶与聚丙烯原位复合材料的相容性研究

在热致液晶共聚酯（ＬＣＰ）与聚丙烯（ＰＰ）的共混体系中引入相容剂（接枝共聚物ＭＡＨ—ｇ－ＰＰ），借助热台偏光显微镜、扫描电镜、差示扫描量热仪、流变仪等方法研究了相容剂对ＰＰ／ＬＣＰ原位复合材料的微观结构和界面性能、结晶行为、流变行为以及力学性能的影响．结果表明：添加相容剂后，基体中的ＬＣＰ微纤分散更均匀，ＬＣＰ微纤长径比Ｌ／Ｄ增大．ＰＰ和ＬＣＰ两相之间有较好的粘连，促进了共混体的结晶，改善了ＰＰ／ＬＣＰ原位复合材料的力学性能．