固相法氯化聚乙烯与聚氯乙烯共混物的形态与性能

研究了聚氯乙烯(PVC)与固相法氯化聚乙烯(CPE)共混物的应力-应变行为和冲击强度对CPE用量和氯含量的依赖关系,考察了共混物形态与性能的关系。动态力学性能和透射电子显微镜的研究结果表明,PVC/CPE为部分相容体系,两相间存在着一定的相互作用,当CPE氯含量为36％～42％,用量为7～15份时,CPE在PVC/CPE共混物中形成比较完整的网络结构、共混物具有更好的抗冲击性能。Brabender流变仪研究表明,CPE能促进PVC的塑化,共混物的加工性优于纯PVC。     

PVC/MBS共混物的形态及力学性能

采用种子乳液聚合方法,在聚丁二烯乳胶粒子上接枝甲基丙烯酸甲酯（MMA）和苯乙烯（St）,制得MBS核壳接枝共聚物,并将其作为增韧剂与聚氯乙烯（PVC）共混制备PVC/MBS共混物。考察了接枝不同MMA和St含量的MBS在PVC中的分散状态及其对PVC/MBS共混物力学性能。结果表明,当MBS壳层中MMA含量增加时,MBS粒子在PVC基体中的分散状态被改善;PVC/MBS共混物的冲击强度随之增加,冲击强度最高时为1117.74 J/m;当MBS中接枝少量St时,PVC/MBS共混物呈现韧性断裂,冲击值最高时为1039.33 J/m;当MBS接枝大量St时,会产生内包容现象,不利于提高PVC共混物的冲击强度。     

Morphology evolution in PS/LDPE blends in a twin screw extruder: Effects of compatibilizer

In order to understand the mixing in polymer extrusion, the morphology of PS/LDPE blends compatibilized with SEBS was simulated based on the Lee and Park model. Experiments were performed in a co-rotating twin screw extruder and a Haake mixer, and the morphology of the compatibilized blends of various compositions was compared with the non-compatibilized ones. The size of the dispersed phase of the compatibilized blend was smaller than the non-compatibilized one, and the blend of the PE matrix had a smaller size in the dispersed phase than the non-compatibilized one. Simulation results were agreed well with experiments, and the Lee and Park model could be applied in the extrusion analysis of compatibilized polymer blends.     

PP/PVC/PP-g-(St-co-MMA)的形态结构

以苯乙烯一甲基丙烯酸甲酯共聚物接枝聚丙烯[PP—g-（St—co—MMA）]为相容剂，利用扫描电子显微镜（SEM）和x射线能谱仪（EDS）对PP／PVC／PP—g-（St—co-MMA）的形态结构进行了研究。由x射线能谱微区分析得到了共混物中氯元素面分布图，对氯元素面分布进行了粒径统计。结果表明，在PP／PVC中加入PP-g-（St—co—MMA）相容剂，共混物亚微观相形态结构发生了变化。PP—g-（St—co—MMA）能够明显降低PP／PVC共混物中PVC分散相的分散尺寸，提高共混物两相之间的相容性。改变相容剂的用量和共混物的组成，都对体系的形态结构产生影响。     

PVC／CPE共混物的结构与性能

从力学性能、冲击断面形貌和流变性等方面综合考察了CPE改性PVC的特点.结果表明,对应不同的CPE用量,冲击强度的增加幅度及断面的形貌不同,流变性也不一样。CPE用量为10～20份时,冲击强度增加迅速,断面形貌和流变性也发生显著变化.CPE在基体中形成网络结构是造成上述变化的主要原因.     

Effect of compatibilizer on the crystallization,rheological, and tensile properties of LDPE/EVOH blends

The effect of the compatibilizer on the crystallization, rheological, and tensile properties of low-density polyethylene (LDPE)/ethylene vinyl alcohol (EVOH) (70/30) blends was investigated. Maleic anhydride-grafted linear low-density polyethylene (LLD-g-MAH) was used as the compatibilizer in various concentrations (from 1 to 12 phr). The interesting effect of compatibilization on the crystallization kinetics of the blends was noted, and the correlation between the morphology and the rheological and tensile properties was also discussed. Morphological analysis showed that the blends exhibited a regular and finer dispersion of the EVOH phase when LLD-g-MAH was added. Nonisothermal crystallization exotherms of the compatibilized LDPE/EVOH blends showed the retarded crystallization of the dispersed EVOH phase, which probably resulted from the constraint effect of the grafted EVOH (EVOH-g-LLD) as well as the size reduction of the EVOH domains. The blends exhibited increased melt viscosity and storage modulus and also enhanced tensile properties with the addition of LLD-g-MAH, which seemed to be attributable to both dispersed particle-size reduction and improved interfacial adhesion. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1245–1256, 1998     

Crystalline structure and phase structure of mLLDPE/LDPE blends

The crystalline structure and phase structure of metallocene linear low density polyethylene (mLLDPE) and low density polyethylene (LDPE) blends were investigated, using a combination of differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), and small-angle X-ray scattering (SAXS) techniques. The samples displayed cocrystallization phenomenon for LDPE of 80 wt% in the blends, indicating good compatibility between the two components under this circumstance; as LDPE content decreased, phase separation arose whereas partial cocrystallization still existed in the blends. Over the whole range of weight fractions, the intrinsic crystal structure of mLLDPE does not change with the addition of LDPE, while enhanced orthorhombic crystalline phase were observed as LDPE content increased. The changes in the thickness of interface layer σ_b, dispersed phase size a_c and integral invariant Q further indicate the existence of partial compatibility between the two phases. Irrespective of the phase inversion, the morphology of the dispersed phase is deduced to be in a transitional state from rod-like shape to flakes within the whole proportional range investigated.     

PVC抗冲击改性剂的喷雾干燥粒子形态研究

针对PVC树脂用抗冲击改性剂丙烯酸类树脂的喷雾干燥粒子堆积形态特征，建立了粒子堆积的模型，并对模型进行了表观密度的理论计算。利用扫描电子显微镜研究了PVC用抗冲击改性剂的喷雾干燥粒子实际形态，提出了提高表观密度的基本思路。     

丁腈橡胶增容丁苯橡胶/聚氯乙烯共混体系

采用一系列结合丙烯腈质量分数不同的丁腈橡胶(NBR)作为丁苯橡胶(SBR)／聚氯乙烯(PVC)不相容共混物的增容剂,研究了SBR／PVC／NBR硫化胶的力学性能,并用扫描电子显微镜、傅里叶变换红外光谱仪和动态黏弹仪研究了该硫化胶的形态结构与相容性。结果表明,结合丙烯腈质量分数为20％～26％的NBR是SBR／PVC的优良增容剂,可提高共混物的力学性能,使SBR相和PVC相达到微细均匀化分散,并在两相之间形成了界面层,使得增容效果达到最佳。     

埃洛石纳米管对PVC/CPE复合材料性能的影响

制备了PVC/CPE/埃洛石纳米管（HNTs）复合材料,研究了HNTs对PVC/CPE复合材料力学性能、微观形貌及热性能的影响.结果显示,HNTs对PVC/CPE材料的增韧效果与基体的韧性及HNTs的添加量有关.当基体韧性较低时,添加少量的HNTs可显著提高PVC/CPE的冲击强度,同时,材料的拉伸强度、弯曲强度和热性能也得到一定的提高.当m（PVC）∶m（CPE）∶m（HNTs）=100∶ 3∶3时,复合材料的冲击强度可达22.17 J/m2,为纯PVC基体树脂的3.4倍,复合材料的冲击断面较粗糙,HNTs在基体中分散较均匀.     

Morphology study of immiscible polymer blends in a vane extruder

This study reports the morphology development of polymer blends in a novel vane extruder in which polymer mainly suffers from elongational deformation field. Rapidly cooled samples of polypropylene/polystyrene (PP/PS) are collected in the vane extruder after stable extrusion. Furthermore, the shape and size of the dispersed phase from initial to final stages are analyzed. In addition, in order to compare the final size of the dispersed phase, different immiscible blends, including polypropylene/polyamide and PP/PS, are prepared by vane extruder and twin‐screw extruder, respectively. The results show that the dispersed phase is made to change rapidly from stretched striations to droplets under the strong elongational deformation field in the vane extruder. Furthermore, the droplet size of dispersed phase of blends prepared by vane extruder is much smaller than that prepared by twin‐screw extruder, indicating that the vane extruder is more efficient in mixing for immiscible polymer blends. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Styrene-co-acrylonitrile resin modifications of PVC/CPE blends

The effects of styrene-co-acrylonitrile resin (AS) on the mechanical properties, morphology, and plasticizing and rheological behaviors of poly(vinyl chloride)/chlorinated polyethylene(PVC/CPE) blends are studied. The results show that the impact strength and the tensile strength are all increased and the plasticizing and rheological behaviors are also improved when a certain amount of AS is added into PVC/CPE blends, which are different in characteristics and regularity from plastics toughened with elastomers. It is blends of brittle—ductile transition regions (i.e., PVC/CPE = 100/10, 100/15) that can obviously be toughened by AS. The analysis of the morphological structure shows that AS promotes the formation of a CPE network that embeds the primary particles of PVC. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1455–1460, 1997     

PVC/CPE/GF复合材料制备及力学性能

采用玻璃纤维(GF)及氯化聚乙烯(CPE)对聚氯乙烯(PVC)协同增韧改性.研究表明,当共混体系中有一定量的GF时,CPE的加入不仅能够改善共混物的韧性,还能够促进GF在PVC基体中的分散,两者协同增韧.随着CPE加入量的增加,GF分散效果增强,PVC/CPE/GF共混物的硬度呈现先显著增强后缓慢增强的趋势、拉伸强度和...     

增容剂LDPE-g-MAH对木质素/聚乙烯吹塑薄膜形貌与性能的影响

研究了低密度聚乙烯与马来酸酐的接枝共聚物LDPE-g-MAH对木质素/低密度聚乙烯共混体系热性能、红外光谱分析力学性能、流变行为以及微观形态的影响.DSC-TG综合热分析表明添加增容剂的共混物的熔融温度降低,热稳定性提高;红外光谱分析表明木质素与LDPE-g-MAH之间存在分子间氢键相互作用,流变性能分析表明共混物体系具有可加工性;扫描电子显微镜（SEM）照片显示添加增容剂后分散相尺寸明显减小,分散程度提高;PE-g-MAH有效提高了木质素/聚乙烯吹塑薄膜的力学性能,且当木质素、聚乙烯和LDPE-g-MAH质量比为25/75/10时,力学性能最优.     

CPE—g—VC改性PVC的研究

选用CPE-g-VC和CPE以物理机械共混方法分别改性PVC树脂。试验结果表明,CPE-g-VC对PVC韧性的改性效果优于CPE,以CPE相当量10份计时,CPE-g-VC改性的共混体系抗冲击强度比CPE改性的高1～2倍。而对塑化性能的影响,两者无明显的差别。     

Mechanical and thermomechanical characterization of PVC/polyalkylacrylate blends

The effect of blending poly(ethyl acrylate) and poly(butyl acrylate) in various proportions with suitably stabilized and plasticized polyvinyl chloride (PVC) was studied with reference to their physical, mechanical, thermal, and morphological properties. The tensile modulus and ultimate tensile strength indicated a rise initially, followed by their steady decrease with increasing concentration of the polyalkyl acrylates. A corresponding behavior of elongation at break and toughness are exhibited. The various polyblends exhibit thermal stability over unmodified PVC, as reflected from their thermomechanical studies, in which the penetration is also inversely related to the respective moduli. The biphasic cocontinuous systems as explicit from the morphological studies support phase mixing at the initial stages, with subsequent phasing‐out tendency, with increasing percentage of polyalkyl acrylate incorporation. The thermomechanical parameters are in conformity to their mechanical parameters, which have been further supported by their morphological studies. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3698–3703, 2006     

Use of poly(ethylene‐co‐vinyl alcohol) as compatibilizer in LDPE/thermoplastic tapioca starch blends

Poly(ethylene‐co‐vinyl alcohol) (EVOH) was used as a compatibilizer to make blends of low‐density polyethylene (LDPE) and plasticized starch (TS). The tensile properties and impact strength were measured and compared with those of neat LDPE. The morphology of the blend specimens, both fractured and unfractured, was observed by scanning electron microscopy. Comparison of the properties showed that the impact strength of the blend improves significantly by the addition of a compatibilizer even with a high TS loading of 40 and 50% (by weight). A high elongation at break almost matching that of neat polyethylene was also obtained. The blend morphology of the etched specimens revealed fine dispersion of the starch in the polyethylene matrix, while the fracture surface morphology clearly indicate that the failure of compatibilized blends occurs mainly by the ductile mode. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3126–3134, 2002     

SAN对PVC／CPE加工行为的影响

采用Ｂｒａｂｅｎｄｅｒ塑化仪和双辊开炼机，研究了几种刚性有机填料ＳＡＮ（苯乙烯和丙烯腈的共聚物）对ＰＶＣ／ＣＰＥ（聚氯乙烯／氯化聚乙烯）共混体加工行为及力学性能的影响。实验表明：这几种ＳＡＮ均有缩短ＰＶＣ／ＣＰＥ塑化时间，改善熔融塑化行为的效能，但不同流动性的ＳＡＮ作用有所差异。还证实了不同加工方法的改性效果不尽相同。     

Structure and Morphology Development in Films of mLLDPE/LDPE Blends During Blowing

Summary: In this work the analysis of the structure orientation, morphology, relaxation time and optical properties of blown films of mLLDPE, LDPE and their blends were performed by using WAXD, SALS, AFM, DSC and rheological and haze tests. For mLLDPE film, the crystals do not present “a”‐axis orientation along the machine direction; a distinct spherulite like superstructure is seen. The film surface is very rough. The values of bulk and surface haze are higher than LDPE and blends, whereas the relaxation time is lower. For LDPE film the (110) planes are parallel and at same time twisted with respect to the layer of the film with the “a”‐axis well oriented along the machine direction. No spherulite superstructure is observed and the surface of the film is more regular. High values of relaxation time are observed. The surface haze is the predominant contribution to the total haze. For the blend films no clear and distinct spherulite structures are observed. The orientation degree increases with composition never approaching that of LDPE. The surface is very more regular and smooth than that of the pure polymers. The haze values are below the values of pure materials. It was underlined that bulk and surface morphology and orientation degree of the crystalline planes along the machine direction dictate the optical properties of the films. Moreover both orientation and morphology are defined by the PE molecular and melt rheology characteristics, processing conditions and blend composition.

Total, bulk and surface haze of mLLDPE/LDPE blend films as a function of composition.