Reactive Compatibilization of Poly(trimethylene terephthalate)/Polypropylene Blends by Polypropylene‐graft‐Maleic Anhydride. Part 1. Rheology,Morphology, Melting,and Mechanical Properties

Poly(trimethylene terephthalate)/polypropylene (PTT/PP) blends were prepared by melt blending. The rheology, morphology, melting, and mechanical properties of PTT/PP blends were investigated with and without the addition of polypropylene‐graft‐maleic anhydride (PP‐g‐MAH). The melt viscosity results showed that the fluid behavior of PTT/PP blends exhibited great disparity to that of PTT but similar to that of PP; the dispersed flexible PP phase in the blends served as a “ball bearing effect” under shear stress, which made the fluid resistance markedly reduced; by contrast, the relatively rigid PTT dispersed phase made only a small contribution to the viscosity. With 5 wt.% PP‐g‐MAH addition during melt processing, both the shear viscosity and the non‐Newtonian index of 70/30 PTT/PP blend were increased over that of the corresponding uncompatibilized one, whereas the shear viscosity of the 30/70 PTT/PP melt decreased slightly indicating that a considerable amount of PP‐g‐MAH did not act as compatibilizer but probably served as plasticizer.

With the increasing of the other component, the melting temperature of the PTT phase showed a slight decrease while the melting temperature of the PP phase showed a slight increase. 5 wt.% PP‐g‐MAH addition had little influence on the melting temperatures of the two components. When PP≤20 wt.%, the cold crystallization temperature of the PTT phase (T_cc (PTT‐phase)) showed little change with the composition; however, it shifted to higher temperature when PP≥30 wt.%. The variations of the T_cc (PTT‐phase), with and without PP‐g‐MAH, suggested that, when PTT was a minor component, the excess PP‐g‐MAH which did not act as compatibilizer might serve as a plasticizer that made the PTT's cold crystallization process to be easier. The SEM results indicated that, for the uncompatibilized blends, the interfaces from particles pulling‐out are clear and smooth, while, for compatibilized blends, the reactive products are at the interfaces. The mechanical properties suggested that PP‐g‐MAH did not result in significant improvement of the toughness of the blend, but the tensile strength increased markedly.     

Morphology and mechanical properties of PP/HMWPE blends

Mechanical properties and morphology of blends of polypropylene (PP) with high molecular weight polyethylene (HMWPE) prepared by coprecipitation from xylene solution are investigated. Compared to blends of PP with commercial high-density polyethylene (HDPE), the mechanical properties of the blends of PP/HMWPE are much superior to those of PP/HDPE blends. Not only is the tensile strength stronger, but also the elongation at break is much higher than that of the PP/HDPE blends of the same composition. These differences increase with increasing HMWPE and HDPE content. Scanning electron microscopy of the fracture surface resulting from the tensile tests shows that the compatibility in PP/ HMWPE blends is much better than that in PP/HDPE blends. This is most likely attributable to the enhanced chain entanglement of HMWPE with the PP in the amorphous phase due to the lower crystallinity, owing to the high molecular weight of the HMWPE, and a much more flexible chain. The thermal behavior and spherulite morphology of both blends are also investigated.     

Adhesion in polyamide/compatibilizer/polypropylene systems

The effect of compatibilization on the adhesion, fracture toughness, morphology, and mechanical properties of isotactic polypropylene (PP)/polyamide 6 (PA) blends was investigated. Maleic anhydride (MAH) functionalized poly-(ethylene-co-vinyl acetate) (EVA-g-MAH) and nonreactive EVA copolymer were used as compatibilizers in binary blends. An attempt of in situ compatibilization via addition of pure maleic anhydride to PA/EVA/PP melt was also made. The blends containing maleated EVA copolymer showed more regular and finer dispersion of phases, better adhesion at the interface, and improved mechanical properties.     

Influence of surface modification of halloysite nanotubes and its localization in PP phase on mechanical and thermal properties of PP/ABS blends

Halloysite nanotubes (HNTs) have been successfully modified using polyethyleneimine (PEI). HNTs and PEI-modified HNTs-filled 80/20 (wt/wt) polypropylene (PP)/acrylonitrile butadiene styrene (ABS) blends and its nanocomposites in the presence of dual compatibilizer have been prepared by melt mixing technique. The refinement in matrix–droplet morphology, selective localization of PEI-modified HNTs, increase in crystallinity of PP phase, formation of β-form of PP crystals and improved dispersion of PEI-modified HNTs in PP phase has resulted in a remarkable improvement in tensile modulus, impact strength and thermal stability of PEI-modified HNTs-filled 80/20 (wt/wt) PP/ABS blends in presence of dual compatibilizer. The increase in tensile modulus, tensile strength and impact strength for PEI-modified HNTs-filled 80/20 (wt/wt) PP/ABS blends in presence of dual compatibilizer are 28.8, 26.6 and 38.5%, respectively.     

Influence of halloysite nanotubes (HNTs) on morphology,crystallization, mechanical and thermal behaviour of PP/ABS blends and its composites in presence and absence of dual compatibilizer

Halloysite nanotubes (HNTs) filled 80/20 (wt/wt) polypropylene (PP)/acrylonitrile butadiene styrene (ABS) blends and its composites in presence and absence of dual compatibilizer (polypropylene grafted maleic anhydride (PP-g-MA), and styrene-ethylene, butylene-styrene triblock copolymer grafted with maleic anhydrite (SEBS-g-MA)) have been prepared using twin screw extruder followed by injection moulding. Significant refinements in dispersed ABS droplets diameter and interparticle distance between dispersed ABS droplets were observed in case of HNTs filled 80/20 (wt/wt) PP/ABS blends and its composites in presence of PP-g-MA and SEBS-g-MA. This has resulted in significant enhancement in tensile and impact properties of HNTs filled 80/20 (wt/wt) PP/ABS blends and its composites in presence of PP-g-MA and SEBS-g-MA. Refinement in morphology of dispersed ABS phase results in decrease in crystallinity of HNTs filled 80/20 (wt/wt) PP/ABS blends and its composites in presence of PP-g-MA and SEBS-g-MA. In addition, HNTs act as heterogeneous nucleating agent for the growth of PP crystals, and hence crystallization rate of HNTs filled 80/20 (wt/wt) PP/ABS blends and its composites in presence and absence of PP-g-MA and SEBS-g-MA increases. Thermal stability also increases in case of HNTs filled 80/20 (wt/wt) PP/ABS blends and its composites in presence and absence of PP-g-MA and SEBS-g-MA.     

Mie散射研究聚合物合金相结构的形成及相尺寸分布

本文应用Mie散射理论研究了聚丙烯 /尼龙 1 0 1 0合金的相结构与形态 ,计算了相尺寸分布。其结果与电子显微镜及Rayleigh散射结果进行了比较。     

Properties of Compatibilized Nylon 6/ABS Polymer Blends

Nylon 6/poly(acrylonitrile‐butadiene‐styrene)(ABS) blends were prepared in the molten state by a twin‐screw extruder. Maleic anhydride‐grafted polypropylene (MAP) and solid epoxy resin (bisphenol type‐A) were used as compatibilizers for these blends. The effects of compatibilizer addition to the blends were studied via tensile, torque, impact properties and morphology tests. The results showed that the additions of epoxy and MA copolymer to nylon 6/ABS blends enhanced the compatibility between nylon 6 and ABS, and this lead to improvement of mechanical properties of their blends and in a size decrease of the ABS domains.     

Effect of Abrasives on Three-Body Abrasive Wear Behaviour of Particulate-Filled Polyamide66/Polypropylene Nanocomposites

Polyamide66/polypropylene (PA66/PP) blend, graphite (Gr)-filled PA66/PP composite and nanoclay (NC)-filled PA66/PP nanocomposites were prepared by twin screw extrusion and injection molding. Three-body abrasive wear behaviour of the injection moulded composites was carried out using a rubber wheel abrasion wear tester. In this study, angular silica sand and quartz particles of size ranging from 200 to 250 μm were used as dry and loose abrasives. The tests were carried out for 150, 300, 450 and 600 m abrading distances at a constant load of 36 N. It was observed that inclusion of particulate fillers in PA66/PP have significant influence on wear under varied abrading distances for different abrasive particles. Further, it was found that NC-filled PA66/PP nanocomposite exhibited lower wear rate compared to Gr filled ones for different abrasive particles. In addition, the worn surfaces of the samples were examined by scanning electron microscopy (SEM) and the morphology was also discussed.     

利用红外光谱成像技术研究PP/PE共混物

利用红外光谱对不同比例条件下制备的PP PE共混物进行了研究 ,通过对PP ,PE的特征吸收峰的分析 ,发现聚丙烯 (PP)特征峰峰面积与聚乙烯 (PE)特征峰峰面积的比值与PP/PE共混物的质量比之间存在较好的对应关系。利用特征吸收峰面积之比 ,借助红外成像技术对PP纤维热压在PE薄膜上制备的样品的研究得到了复合共混物的分布信息 ,发现其成像结果与偏光显微镜的结果有很好的吻合。实验研究结果表明采用红外成像技术 ,利用特征吸收峰面积之比可以进行对聚合物共混物的分相行为的研究。     

Compatibilization by Olefin Block Copolymer (OBC) in Polypropylene/Ethylene-Propylene-Diene Terpolymer (PP/EPDM) Blends

The compatibilization by olefin block copolymer (OBC) in the blends of polypropylene (PP)/ethylene-propylene-diene terpolymer (EPDM) and the phase morphology of the ternary blends were investigated by rheology, scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD) measurements. It was found that the PP/EPDM blends exhibited enhanced mechanical properties in the presence of OBC. The addition of OBC had a significant influence on the phase separation behavior of the blends. For the PP/EPDM-50/50 heterogeneous blends, the addition of 15 phr OBC enabled the two-phase morphology to change from a droplet-matrix structure to a co-continuous one. In the temperature range of 150 to 200 °C, OBC was shown to have a better compatibility with PP than EPDM. The changes in viscosity ratio of the dispersed phase to matrix phase caused by adding OBC might be the dominant factor in controlling the coalescence of the dispersed phase domains. For the crystallization behavior of PP/EPDM/OBC ternary blends, OBC was found to have an induction effect on the formation of β-crystals of PP that was not proportional to the volume of OBC addition. In addition, DSC results showed that PP could induce the OBC crystallization and improve the crystallization temperature of OBC. The existence of simultaneous crystallization behavior between PP and OBC was also observed. A possible mechanism of phase evolution induced by crystallization was proposed.     

Relationship between Microstructure and Mechanical Properties of Ethylene-Octene Copolymer Reinforced and Toughened PP

Polypropylene (PP)/ethylene-octene copolymer (POE) blends with 10–50wt% POE composition were prepared using a twin-screw extruder in the melt state. Mechanical properties of PP and PP/POE blends were tested and the effect of POE content on the crystalline morphology and structure, melting and crystallization behavior, compatiblilty, phase morphology, and the interface cohesiveness of the blends were investigated by polarizing optical microscope (POM), wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), and scanning electron microscopy (SEM). The relationship between mechanical properties and microstructure of the PP/POE blends is discussed. The results showed that POE had a dual function of both reinforcing and toughening PP in the range from 10–40wt%, which was attributed to the integrated functions of the degree of crystallinity of the PP phase, phase morphology, and interface cohesiveness of the blend.     

On Localization of Clay Nanoparticles in Polypropylene/poly(Lactic Acid) Blend Nanocomposites: Correlation with Mechanical Properties

Two polypropylene (PP)/polylactide (PLA)/clay ternary nanocomposite systems, i.e. PP-rich and PLA-rich ones, each containing various amounts of one of two types of clay, were prepared by one step melt compounding in a twin screw extruder. The microstructures of the developed systems were correlated with tensile and impact properties. A theoretical calculation using wetting coefficients was used for predicting the clay nanoparticles localization in the blends. The nanoparticles were almost completely located within the PLA phase in both the PP-rich and PLA-rich systems, in good agreement with the predictions. Addition of a compatibilizer led to localization of the nanoparticles at the interfaces of the blends. From the wide angle X-ray scattering (WAXS) spectra it was concluded that the incorporation of clay led to intercalated structures in the both systems. The increase in impact toughness of the compatibilized blend nanocomposites, with respect to the uncompatibilized ones, was attributed to the weakened interfacial debonding in the presence of the interfacial-localized nanoparticles.     

Preparation and Combustion Behavior of Polyamide 6/Polypropylene/Clay Nanocomposites

Polyamide 6(PA 6)/Polypropylene (PP) blends as well as PA 6/PP/clay composites were prepared by melt compounding. The distribution of clay was characterized by transmission electron microscopy. The combustion surface morphology as well as product composition after burning were studied by scanning electron microscopy along with electro-probe microanalysis. Moreover, the flame retardance and thermal stability were evaluated by a cone calorimeter together with thermogravimetric analysis. The results showed that the clay was selectively located in the PA6 phase. It is proposed that, in the presence of clay, the combustion surface changed from a branch-shaped structure to a compact carbonaceous–silicate structure. When the clay content was 3 phr, the layered silicates became enriched on part of the surface and formed an island-like structure; the islands displayed a loose cinders structure with much higher silicon content, in contrast to a branch-shaped surface with low silicon content of the surrounding polymer substrate. As the clay content continued to increase, the char covered most of the combustion surface and more clay accumulated on the burning surface. In addition, the clay particles promoted the formation of the carbonaceous–silicate structure. The peak of the heat release rate of the PA6/PP blend decreased with increasing addition of clay and the thermal stability of the PA6/PP blend also improved.     

Effects of Blend Ratio on Rheology,Morphology, Mechanical and Oil-Resistant Properties in Chlorinated Polyethylene Rubber and Copolyamide Blends

The elastomeric chlorinated polyethylene (CPE) blended with a low melting point copolyamide (PA6/PA66/PA1010, PA) was prepared by a melt mixing technique. The mixing characteristics of the blends were analyzed from the rheographs. The influence of copolyamide (PA) content on the morphology, mechanical properties, crystallization and oil-resistance, and the addition of compatibilizers on the mechanical properties were also systematically investigated. Morphological examinations clearly revealed a two-phase system in which CPE/PA blends exhibit a cocontinuous morphology for 50/50 composition, and the continuous phase of PA turns into a disperse phase for 70/30, 80/20, and 90/10. There is a distinct interface between the two phases. The mechanical properties, crystallization, and oil-resistance have a strong dependence on the amount of PA. The blends with higher proportions of PA have superior mechanical properties; they are explained on the basis of the morphology of the blend and the cystallinity of PA. In addition, compatibilizers, including chlorinated polyethylene-graft-copolyamide (CPE-G-PA), chlorinated polyethylene-graft-maleic anhydride (CPE-G-MAH), ethylene-n-butyl acrylate-monoxide (EnBACO), and ethylene-n-butyl acrylate-monoxide-graft-maleic anhydride (EnBACO-g-MAH) were added into the blends. Tensile strength and elongation at break go through a maximum value at a compatibilizer resin content (on the basis of the total mass of the blend) of 20 wt% while the PA content is 30 wt%.     

Effect of pre-irradiation PPO-grafted maleic anhydride on structure and properties of PPO-g-MAH/PA66 blends

The pre-irradiation polyphenylene oxide (PPO)-graft-maleic anhydride (PPO-g-MAH) was carried out by reactive extrusion. The chemical structure of PPO-g-MAH was characterized by means of Fourier-transform infrared spectroscopy. The wettability of PPO-g-MAH was characterized by the contact angle method. The blends of PPO-g-MAH/polyamide 66 (PA66) were prepared. Compared with the PPO/PA66 blends, mechanical properties of PPO-g-MAH/PA66 blends were distinctly improved. Smaller dispersed particle sizes with narrower distribution were found in PPO-g-MAH/PA66 blends, via field-emitted scanning electron microscopy. Rheological properties of PPO-g-MAH/PA66 blends were studied with a rotational rheometer.     

Simultaneously Enhancing Mechanical Properties and Melt Flow Ability of Polyamide 6 by Blending with a Hyperbranched Polymer

A series of polyamide 6/hyperbranched polymers (PA6/HBP) blends with different HBP contents was prepared by melt processing using a twin-screw extruder. The HBP was synthesized on the basis of pentaerythritol and dimethyl terephthalate according to a one-step method. The melt flow behavior, crystallization behavior, morphology, and mechanical properties of the PA6/HBP blends were investigated. The results showed that the melt flow index of the blends was greatly improved by a small amount of HBP. The yield strength, tensile modulus, Izod impact strength, and flexural strength of samples were simultaneously enhanced from 54.6 MPa, 0.5 GPa, 3.8 kJ/m², 56.9 MPa for pure PA6 to 61.1 MPa, 0.7 GPa, 5.3 kJ/m², 67.1 MPa for PA6 blends with 2.0 wt% HBP, respectively. The PA6/HBP blends showed the higher content of α-form crystal and a higher degree of crystallinity than those of pure PA6.     

THERMAL BEHAVIOR OF PP/PA6 BLENDS UNDER DYNAMIC CONDITIONS. THE EFFECT OF DIFFERENT INTERFACIAL AGENTS BASED ON CHEMICALLY MODIFIED ATACTIC POLYPROPYLENE

The thermal behavior in dynamic conditions of polypropylene/polyamide 6 (PP/PA6) blends with a modified interphase is discussed in terms of the crystallinities of the polypropylene and polyamide components imposed by the processing step conditions and after removal of those constraints by holding the blends 5 min in the molten state in the calorimeter. As interfacial agents, two based on succinic anhydride or succinil-fluoresceine grafted atactic polypropylenes were used. The experimental program was run following the Box-Wilson experimental design methodology. Thermal scans were made using round samples (5 mm diameter and 100 μm thick) cut from compression-molded sheets with morphologies and macroscopic behavior studied previously. Changes of the amount of crystallinity of each polymer in the modified blends are contrasted with the tensile strength values of the heterogeneous materials as a whole; evidence of the different roles played by each interfacial agent acting at the interface among blend components is shown.     

Phase Morphology and Dynamic Mechanical Properties of Nylon 6 Based Blends Prepared via Successive In Situ Ring Opening Polymerization

Acrylonitrile butadiene styrene (ABS)/nylon 6 blends were prepared via in-situ polymerization and a compatibilization method with various blend compositions. The monomer of nylon 6 (?-caprolactam) was polymerized using activated anionic ring opening polymerization in the presence of ABS. Hexamethylene diisocyanate (HDI) and styrene maleic anhydride (SMA) were used as microactivator and macroactivator at different concentrations. Phase morphology and dynamic mechanical properties were evaluated; and the blending method was compared with ordinary reactive extruding (melt blending). In samples with dispersed structure, the dispersed particle size decreased with increasing SMA. Also, the effects of SMA at lower levels of HDI were more significant, probably due to competition between the activators in the reaction. In some of the in-situ prepared blends, even in the co-continuous structure, particles with sizes under 500 nm were observed. A noteworthy observation in micrographs was that the sizes of the dispersed particle prepared by the in situ method were less than those prepared by the compounding method. Even the uncompatibilized in situ samples had a finer particle size in comparison with the ordinary compatibilized samples. The phase inversion point was also investigated; it was affected by both micro and macro activator concentrations. At higher HDI or SMA content, a lower phase inversion concentration (φ_Nylon6) was observed. In samples with an ABS dispersed phase, after in situ compatibilization using SMA, extraction of the ABS phase did not happen easily in the given time because of the surrounding copolymer at the particles surfaces. These blends had ultra-small particles (under 200 nm). Comparison of changes in the Tg_ABS and Tg_Nylon6 showed another interesting result. While the Tgs of samples prepared by the compounding method shifted about 3°C, the Tgs of samples prepared by the in situ method shifted more obviously (around 4–30°C). This indicated the powerful compatibilization caused by the in situ polymerization and compatibilization method. All results confirmed that the in situ polymerization and compatibilization method should be considered to be useful for production of ABS/nylon 6 blends.     

Reactive Compatibilization of Poly(trimethylene terephthalate)/Polypropylene Blends by Polypropylene‐graft‐Maleic Anhydride. Part 2. Crystallization Behavior

The crystallization behavior of uncompatibilized and reactive compatibilized poly(trimethylene terephthalate)/polypropylene (PTT/PP) blends was investigated. In both blends, PTT and PP crystallization rates were accelerated by the presence of each other, especially at low concentrations. When PP content in the uncompatibilized blends was increased to 50–60 wt%, PTT showed fractionated crystallization; a small PTT crystallization exotherm appeared at ～135°C besides the normal ～175°C exotherm. Above 70 wt% PP, PTT crystallization exotherms disappeared. In contrast, PP in the blends showed crystallization exotherms at 113–121°C for all compositions. When a maleic anhydride‐grafted PP (PP‐g‐MAH) was added as a reactive compatibilizer, the crystallization temperatures (T _c ) of PTT and PP shifted significantly to lower temperatures. The shift of PTT's T _c was larger than that of the PP, suggesting that addition of the PP‐g‐MAH had a larger effect on PTT's crystallization than on PP due to reaction between maleic anhydride and PTT.

The nonisothermal crystallization kinetics was analyzed by a modified Avrami equation. The results confirmed that PTT's and PP's crystallization was accelerated by the presence of each other and the effect varied with blend compositions. When the PP content increased from 0 to 60 wt%, PTT's Avrami exponent n decreased from 4.35 to 3.01; nucleation changed from a thermal to an athermal mode with three‐dimensional growths. In contrast, when the PTT content increased from 0 to 90 wt% in the blends, changes in PP's n values indicated that nucleation changed from a thermal (0–50 wt% PTT) to athermal (60–70 wt% PTT) mode, and then back to a thermal (80–90 wt% PTT) mode. When PP‐g‐MAH was added as a compatibilizer, the crystallization process shifted considerably to lower temperatures and it took a longer crystallization time to reach a given crystallinity compared to the uncompatibilized blends.     

Mechanical Properties,Rheology, and Crystallization of Epoxy-Resin-Compatibilized Polyamide 6/Polycarbonate Blends: Effect of Mixing Sequences

Blends of polyamide 6 (PA6)/polycarbonate (PC)/epoxy resin (EP) were melt blended with three different mixing sequences. Their mechanical properties, crystallization, and rheological behaviors, as well as the morphology, were investigated via mechanical testing, differential scanning calorimetry (DSC), dynamic rheometry, and scanning electron microscopy (SEM). It was noted that the mixing sequences affected the distribution of EP in the PA6 matrix, as well as the reactivity of EP with PA6 and PC. Mechanical testing showed that the blends prepared by the first (S₁, blending PA6, PC, and EP simultaneously) and second mixing sequences (S₂, blending PC with a premixture of PA6/EP) had higher notched Izod impact strengths due to the formation of PA6-EP-PC block copolymer (named as the AEC structure) during compounding, as evidenced by the results of dynamic rheology and SEM. Whereas for the third sequence (S₃, blending PA6 with a premixture of PC/EP), EP could barely react with PA6 and PC, leading to little formation of AEC structure, which resulted in a poor notched Izod impact strength of the blends. The incorporation of EP actually acted as a plasticizer to improve the elongation at break of the S₃ blends. In addition, the DSC results and SEM observations showed that there were distinct differences in the crystallization and morphology of the samples prepared by the different mixing sequences.