The Use of Ethylene/Propylene Copolymers as Compatibilizers for Recycled Polyolefin Blends

Compatibilizing effects of ethylene/propylene (EPR) diblock copolymers on the morphology and mechanical properties of immiscible blends produced from recycled low‐density polyethylene (PE‐LD) and high‐density polyethylene (PE‐HD) with 20 wt.‐% of recycled poly(propylene) (PP) were investigated. Two different EPR block copolymers which differ in ethylene monomer unit content were applied to act as interfacial agents. The morphology of the studied blends was observed by scanning‐ (SEM) and transmission electron microscopy (TEM). It was found that both EPR copolymers were efficient in reducing the size of the dispersed phase and improving adhesion between PE and PP phases. Addition of 10 wt.‐% of EPR caused the formation of the interfacial layer surrounding dispersed PP particles with the occurrence of PE‐LD lamellae interpenetration into the layer. Tensile properties (elongation at yield, yield stress, elongation at break, Young's modulus) and notched impact strength were measured as a function of blend composition and chemical structure of EPR. It was found that the EPR with a higher content of ethylene monomer units was a more efficient compatibilizer, especially for the modification of PE‐LD/PP 80/20 blend. Notched impact strength and ductility were greatly improved due to the morphological changes and increased interfacial adhesion as a result of the EPR localization between the phases. No significant improvements of mechanical properties for recycled PE‐HD/PP 80/20 blend were observed by the addition of selected block copolymers.     

高分子共混物的相结构对力学性能的影响

本文以聚丙烯 尼龙1010(PP PA1010)共混体系为模型研究了高分子共混物的微观相结构对宏观力学性能的影响,并通过微观力学模型来预测共混物的拉伸强度。通过光散射试验和扫描电镜结果讨论了两相平均弦长比(L1 L2)以及分散相的质心相关距(D)与拉伸性能的关系。结果表明,当分散相一定时,拉伸强度随两相相对尺寸的增大和分散相颗粒相关性的减弱而减小。理论计算的分散相最小体积分数与相形貌观察的结果非常接近,添加增容剂的体系,由于改善了界面粘合,使理论预测值与试验结果很好的吻合。     

Mechanical Properties and Morphology of Recycled. Plastic Wastes by Solution Blending

In this study, bottles of mineral water and yogurt as well as Styrofoam bowls were recycled and identified by infrared spectroscopy as poly(vinyl chloride) (PVC), high-impact polystyrene (HIPS), and polystyrene (PS). Solution blending was employed to make polymer blends from these recycled plastics, including PVC/PS, PVC/HIPS/PS blends, and PVC/HIPS blends with or without a com-patibilizer, styrenelp-chlorostyrene (ST-CMS). Thermal behavior from differential scanning calorimetry was used to examine the compatibility of the blends. For the PVC/PS and PVC/HIPS/PS systems, it is found that although the third component (HIPS) may not be good enough as a compatibilizer, the addition of HIPS to the two-component blend (PVC/PS) may enhance the mechanical properties at the specific composition, especially for the blends at the intermediate concentrations. For PVC/HIPS blends with the ST-CMS copolymer as a compatibilizer, all the mechanical properties of the blends except the elongation at break, in general, increased with increasing the concentration of compatibilizer due to the increase of compatibility. The abnormal fracture strain was attributed to the differences in adhesion when various amounts of ST-CMS was added. The results of mechanical properties of the blends were consistent with the morphology from scanning electron microscopy.     

Morphology and Mechanical Properties in Polymer Blends of Photocurable Polymer and Polycarbonate

Relationships between the morphologies and mechanical properties of binary blends of a photocurable polymer (2‐propenoic acid, (octahydro‐4,7‐methano‐1H‐indenediyl) bis(methylene)ester; DCA) and a linear polymer (poly(4,4′‐cyclohexylidene bisphenol carbonate); PCz) have been investigated. The blend films are prepared by in situ photopolymerization of homogeneous mixtures of a DCA‐monomer and PCz. The phase structure has been converted from a semi‐interpenetrating polymer networks (semi‐IPN) structure to a bicontinuous structure by controlling the cure temperature. Bicontinuous phase‐separated structures can be obtained by curing a wide range of compositions of 17–50 wt.‐% PCz at high temperatures. Miscible semi‐IPN structures are attained by means of photopolymerization below the glass transition temperature of the homogenous mixture before performing photoirradiation, such that magnetic relaxation measurements showed the blend to be miscible in the 10 nm order. The tensile strength and modulus reached a maximum in those blends having an intermediate vague phase structure between semi‐IPN and bicontinuous structures that have a strong interfacial interaction, which leads to incomplete phase decomposition in the PCz‐rich matrix phase. The maximum strength and modulus prepared under optimum condition are inferior to those of the individual components. In contrast, the elongation and break energy are greatly improved in those blends with bicontinuous structures having a diffused phase boundary.

DCA‐rich domain size in bicontinuous structure for DCA/PCz system, as a function of cure temperature; (□) 17 wt.‐% PCz, (○) 30 wt.‐% PCz, and (?) 50 wt.‐% PCz.     

EPDM/CIIR Blends: Effect of EPDM Grade on Mechanical Properties

Blends of chlorobutyl rubber (CIIR) with two grades of ethylene-propylene diene monomer rubber (EPDM) were prepared and the effect of blend ratio on the cure characteristics, hot air ageing resistance, steam ageing resistance, and mechanical properties were evaluated. The blend of CIIR with EPDM grade 301 T showed additive behavior and the blend with the other grade of EPDM (NDR 4640) showed synergistic behavior.     

Filler Wetting in Miscible ESBR/SSBR Blends and Its Effect on Mechanical Properties

The selective wetting behavior of silica in emulsion styrene butadiene rubber (ESBR)/solution styrene butadiene rubber (SSBR) blends is characterized by the wetting concept, which is further developed for filled blends based on miscible rubbers. It is found that not only the chemical rubber–filler affinity but also the topology of the filler surface significantly influences the selective filler wetting in rubber blends. The nanopore structure of the silica surface has been recognized as the main reason for the difference in the wetting behavior of the branched ESBR molecules and linear SSBR molecules. However, the effect of nanopore structure becomes more significant in the presence of silane. It is discussed that the adsorption of silane on silica surface constricts the nanopore to some extent that hinders effectively the space filling of the nanopores by the branched ESBR molecules but not by the linear SSBR molecules. As a result, in silanized ESBR/SSBR blends the dominant wetting of silica surface by the tightly bonded layer of SSBR molecules causes a low‐energy dissipation in the rubber–filler interphase. That imparts the low rolling resistance to the blends similar to that of a silica‐filled SSBR compound, while the ESBR‐rich matrix warrants the good tensile behavior, i.e., good abrasion and wear resistance of the blends.

     

纳米无机粒子选择性分布与迁移对聚合物共混物形态与性能的影响

综述了纳米无机粒子在聚合物合金中选择性分布的影响因素及纳米无机粒子在聚合物中分散的重要性,重点从相行为、相形态、力学性能、电学性能、流变行为、结晶和熔融行为以及光学性能等方面总结了近年来纳米无机粒子在聚合物共混物中的选择性分布与迁移对以聚合物共混物为基体的纳米复合材料的形态和性能的影响。特别强调了如何利用热力学和动力学因素调控纳米无机粒子在聚合物合金中的分布。     

Morphology Development of Immiscible Quaternary Polyolefin and PS Blends

Study of polymer blends that fulfill the current engineering demand has been increased in the last years and multicomponent blends are still a challenge, but increasing the number of components will lead to further complications. We correlated the differences between morphology and blending sequence in quaternary blends of polyolefin with polystyrene, following the available theories that related viscosity and morphology. It was found that high viscous matrices enhance deformation and breakup processes, displaying fibrillar morphologies and finer dispersions. The blending sequence improves the mixing first, by putting all the polyolefin into a ternary blend and after that, adding the polystyrene.     

Morphology and Properties of Poly(propylene)/Ethylene‐Octene Copolymer Blends Containing Nanosilica

The effect of nanosilica addition on the morphology and mechanical properties of blends of isotactic PP and an ethylene/octene copolymer (EOC) is studied. TEM reveals that the well‐dispersed nanoparticles are localized exclusively in the PP phase. In the presence of a maleated PP compatibilizer addition of nanosilica leads to more finely dispersed EOC domains and a finer co‐continuous morphology. The nanoparticles reduce the rate of coalescence of the dispersed phase domains. The mechanical properties depend on the EOC and PP‐g‐MA content. Tensile and flexural properties are significantly enhanced in the presence of the silica nanoparticles, whereas impact properties are not affected. These enhancements are attributed to the favorable microstructure of the blends.

     

Mechanical and Rheological Properties of Poly(ethylene terephthalate)/ Polypropylene Blends

Poly(ethylene terephthalate) and polypropylene (PET/PP) were compounded and pelletized with a single-screw extruder. Standard ASTM tensile test specimens were made by injection moulding. The blends are stronger and stiffer than the plain PP specimens. The addition of a compatibilizer, EPOLENE E-43, is found to improve the strength and stiffness of the blends at loadings of 50% and 70% PET. At 10% PET loading, E-43 has the opposite effect of slightly reducing the tensile properties. All the blends are more brittle relative to either plain PET or PP. The addition of E-43 results in negligible improvement in the elongation at break. E-43 is also found to be an effective lubricant in improving the processability of the blends. The blends with E-43 added have lower viscosities and less shear-thinning characteristics than those without E-43. © 1997 SCI.     

增容剂对PP/回收PET共混物性能的影响

采用熔融共混的方法,制备了聚丙烯(PP)/回收聚对苯二甲酸乙二酯(r-PET)共混物,研究了增容剂甲基丙烯酸缩水甘油酯接枝聚丙烯(PP-g-GMA)对共混物力学性能、热稳定性的影响。结果表明:增容剂的加入能提高共混物的拉伸强度和拉伸模量;加入增容剂能显著提高共混物的热分解温度,增容剂使r-PET的熔点降低;增容剂对PP的结晶性能影响与熔融温度有关。     

Toughening of Epoxy Resins with Thermoplastics: 3. An Investigation into the Effects of Composition on the Properties of Epoxy Resin Blends

Three different epoxy resins, based on the diglycidylether of bisphenol A (DGEBA), triglycidyl-p-aminophenol (TGPAP) and tetra-glycidyldiaminodiphenylmethane (TGDDM), which are di-, tri- and tetrafunctional, respectively, were mixed in varying proportions and cured with both 3,3′-diaminodiphenylsulphone and 4,4′-[1,4-phenylene(1-methylethylidene)]bis(2,6-dimethylbenzenamine) (EPON 1062-M from Shell). All the blends could be satisfactorily cured and gave homogeneous materials. The dynamic mechanical and fracture properties of the cured materials were measured. It was found that the glass transition temperature varied with composition systematically, whereas values of the strain energy release rate (G_1c) and the stress intensity factor (K_1c) showed relatively small variations with the blend composition. Toughened epoxy resins were prepared by adding a polyetherimide (PEI), in varying proportions, to the resin mixture. The ‘toughenabilities’ of different resins, or resin mixtures, were compared. This showed that the 75/25 TGPAP/DGEBA resin mixture was the most toughenable. Adding 20% of PEI led to a more than three-fold increase of the G_1c value. © of SCI.     

Morphology and Thermal Properties of Compatibilized PA12/PP Blends with Boehmite Alumina Nanofiller Inclusions

Boehmite alumina nanoparticles are added to PP‐g‐MAH‐compatibilized blends of PA 12 and PP to study the effects of nanoparticle loading in the resulting composites. WAXD and SEM data suggest that the nanoparticles enhanced the coalescence of PP. DSC, DMA, and TGA reveal that the final properties such as crystallization temperature, flexural storage modulus, thermal degradation temperature, etc., improve with increasing nanoparticle loading for blend/based composites. FTIR results show that the nanoparticles interfere with the interfacial activity at 5 wt% nanoparticle loading. All results are compared between the neat polymers and the compatibilized blend and show that despite a slight increase in dispersed‐phase domain size, all other properties improve with the addition of AlO(OH).

     

Preparation and Assessment of Phase Morphology,Rheological Properties,and Thermal Behavior of Low-Density Polyethylene/Polyhexene-1 Blends

In this work, polyhexene-1 (PH-1) is synthesized by polymerization of hexane-1 with Ziegler–Natta catalyst and melt blended with low-density polyethylene (LDPE). The phase morphology, rheology, crystallization, and thermal behavior of (LDPE)/PH-1 blends are investigated. A good compatibility is observed in the blends up to 10?wt% PH-1 and the most of the droplets in the fractured surface are covered with and buried in the LDPE matrix and at higher percentage the droplet particle size significantly increased. The effect of microstructure of the blends on the flow behavior is studied by small amplitude oscillation rheology. By decreasing the compatibility and increasing the particle size, the Cole–Cole plots are deviated from the semi-circular shape at higher percentages than 10?wt% of PH-1. The change in the crystallization and melting behavior of LDPE in the blends are studied by differential scanning calorimetry and X-ray diffraction (XRD). It is found that by increasing the PH-1 the melting temperature of LDPE decreased from 112.5 to 110.8°C and crystallization temperature increased from 95.2 to 97.7°C which is evident of the nucleation effect. The intensity of (110) peak in XRD test declined as a remake of amorphous part of LDPE and the degree of crystallinity of LDPE decreased from 28 to 22% at 20?wt% PH-1.     

原位接枝改性白炭黑补强天然橡胶的性能研究

以天然橡胶为母胶,双-(γ-三乙氧基硅基丙基)四硫化物(Si-69)为改性剂,制备了天然橡胶/原位接枝改性白炭黑。利用红外光谱、橡胶综合加工分析仪、扫描电镜等手段综合分析了白炭黑改性前后对橡胶的补强性能的影响。结果表明,白炭黑经原位接枝改性后,在橡胶基体中的分散性和与橡胶基体的相容性均有改善,胶料加工安全性和硫化效率均有提升,橡胶综合物理机械性能提升明显。     

Melt Viscosities and Mechanical Properties of PC/SAN Blends

Abstract

Melt viscosities and mechanical properties of polycarbonate (PC), styrene-acrylonitrile copolymer (SAN), and their blends were studied. PC and SAN were melt blended at different compositions using a single screw extruder. Melt viscosities were measured with a capillary rheometer. The melt viscosity test showed that increasing the PC content increases the viscosity of the blends, and melt viscosities of blends are intermediate between the values of PC and SAN. Standard mechanical property tests were performed on injection molded ASTM test specimens. Tensile strength and modulus increase but elongation at break decreases when the SAN content increases. Notched Izod impact strength decreases rapidly with the addition of SAN into PC. Unnotched impact strength is higher than notched impact strength and is less sensitive to the addition of SAN.     

Structure and Properties of Compatible PPSF‐Rich Blends with PET

Summary: New PPSF/PET (poly(phenyl sulfone)/poly(ethylene terephthalate)) blends rich in PPSF were obtained by direct injection molding. Biphasic morphologies with a very large interface area/dispersed phase volume ratio were obtained and were attributed to a low interfacial tension in the melt state, a consequence of the reactions observed between the components of the blends. This favorable morphology led to small strain mechanical properties close or slightly above those predicted by the direct rule of mixtures, and more significantly, to elongations at break of the blends higher than that of the PPSF matrix.

Morphology of the cryogenically‐broken etched surface of a PPSF/PET 75/25 blend.     

硫黄用量对天然胶乳膜性能的影响

采用凝固剂浸渍法制备天然胶乳硫化胶膜,并对其结构和性能进行研究。结果表明：天然胶乳预硫化程度随硫黄用量的增加而增大;胶膜硫化后的交联程度随硫黄用量的增加先增大后减小,在硫黄用量为1.25份时达到最大值;拉伸强度随硫黄用量的增加先增大后减小,在硫黄用量为1份时达到最大值,而拉断伸长率呈下降趋势;当硫黄用量为1份时达到最佳致密性。     

Mechanical and Morphological Properties of Polypropylene and Regenerated Tire-Rubber Blends

Mechanical properties and morphology of blends prepared from polypropylene (PP) and 5–20 wt% of regenerated tire-rubber (RgR) were studied. The samples were prepared in a twin-screw extruder. The addition of maleic anhydride-functionalized polypropylene (PP-g-MAH) was also investigated. Tensile and flexural moduli, tensile strength at break, elongation at break and Izod impact resistance at 23°C were increased by the addition of 15 wt% of regenerated rubber and 5 wt% of PP-g-MAH. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) analyses showed some interaction between PP and RgR and considerable modification of the compatibilized mixture morphology. The fracture surface of the blend with PP-g-MAH showed a better interaction between the PP matrix and the regenerated rubber domains, for all blends. Well-dispersed particles of the rubber in the polypropylene matrix were observed. DSC showed that PP crystallizes on cooling at lower temperatures as the RgR content increases. The decrease in crystallization temperature is more evident for blends with 5 wt% PP-g-MAH.