Preparation and properties of polyamide 6/polypropylene–vermiculite nanocomposite/polyamide 6 alloys

Polypropylene–vermiculite nanocomposites can be achieved by simple melt mixing of maleic anhydride‐modified vermiculite with polypropylene. Maleic anhydride acts either as a compatibilizer for the polymeric matrix or as a swelling agent for the silicate. Compatibilized blends are injection molded directly from polyamide 6 and polypropylene–vermiculite nanocomposites. Scanning electron microscopy observation reveals that a two‐phase structure consisting of polypropylene–vermiculite nanocomposite and polyamide 6 is formed in the blends. The absence of vermiculite reflections in the X‐ray powder diffraction patterns indicates that the polypropylene–vermiculite phase exhibits nanocomposite characteristics. Tensile test shows that the tensile modulus of the polymer alloy tends to increase with increasing polypropylene–vermiculite nanocomposite content. The tensile strength of composite containing 8 wt % vermiculite is higher than that of pure polyamide 6. Finally, the thermal properties of the nanocomposites are determined by dynamic mechanical analysis, differential scanning calorimetry, and thermogravimetric measurements. The effects of maleic anhydride addition on the formation of polypropylene–vermiculite nanocomposite reinforcement and on the mechanical properties of composites are discussed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2330–2337, 2002     

Interfacial adhesion in polyethylene–kaolin composites: Improvement by maleic anhydride-grafted polyethylene

Polyethylene–kaolin composites were investigated with a special emphasis on the control of the interfacial adhesion. Both matrix and filler were modified for this purpose. A stearic acid and maleic anhydride-grafted polyethylene were used as potential interfacial agents and the efficiency of aminosilane-surface-treated kaolin was considered. Tensile strength, elongation, impact strength, and melt index were currently measured in relation to the processing conditions. Enhanced interfacial filler-polymer adhesion progressively results in an decreased melt index. This has been clearly shown by comparing the effect of two polymeric additives to the polymer matrix, i.e., a maleic anhydride-grafted HDPE (MAGPE) and an unmodified HDPE of a similar melt index. Compared to low molecular weight additives, such as stearic acid and aminosilane, MAGPE has proved to be a very efficient additive in improving the impact resistance of HDPE–kaolin composites even at low contents. © 1995 John Wiley & Sons, Inc.     

Studies on the Effect of Reactive Polypropylene on the Properties of Filled Polyolefin Composites. Part 1. Advantages of Solid-Phase-Grafted Maleated Polypropylene Over Melt-Phase-Modified Polymers

The results summarize the problem associated with grafting of maleic anhydride (MAH) on polypropylene (PP) in the melt phase and also describe a new method for grafting PP with MAH in the solid phase. The effectiveness of the solid phase modified maleated polypropylene (MAH-PP) as interphase modifier has been documented by comparing the properties of calcium carbonate filled polypropylene composites (PP-CaCO₃) treated with solid phase modified MAH-PP with that of the melt phase modified MAH-PP treated composites. The solid-phase modification of PP by MAH is nontoxic and is also free from unreacted MAH. The modifier also improves the tensile strength and impact resistance of unmodified PP-CaCO₃ composites.     

Influence of microstructure and flexibility of maleated styrene-b-(ethylene-co-butylene)-b-styrene rubber on the mechanical properties of polyamide 12

The present investigation deals with the mechanical and morphological properties of binary polyamide 12/maleic anhydride-grafted styrene-b-(ethylene-co-butylene)-b-styrene rubber (PA12/SEBS-g-MA) blends at varying dispersed phase (SEBS-g-MA) concentrations. Tensile behavior, impact strength and crystallinity of these blend systems were evaluated. Influence of microstructure, dispersed phase particle size, and ligament thickness on the impact toughness of the blend was studied. DSC data indicated an increase in crystallinity of PA12 in the blends. Tensile modulus and strength decreased while impact strength and elongation-at-break increased with the elastomer concentration. The enhanced properties were supported by interphase adhesion between the grafted maleic groups of rubber with polar moiety of polyamide 12. Analysis of the tensile data employing simple theoretical models showed the variation of stress concentration effect with blend composition.     

剪切作用下POE-g-MAH和PP-g-MAH对PA1010/PP共混物的增容作用

采用熔融共混的方法制备了聚酰胺1010/聚丙烯（PA1010/PP）共混物,通过扫描电镜、力学性能和差示扫描量热等方法研究了剪切作用下马来酸酐接枝乙烯-辛烯共聚物（POE-g-MAH）和马来酸酐接枝聚丙烯（PP-g-MAH）对PA1010/PP共混物的增容作用。结果表明,同样条件下,PP-g-MAH增容体系的相区尺寸较小,相界面更模糊,PP相的结晶温度和结晶度明显提高,共混物的拉伸强度和冲击强度均高于非增容体系。而POE-g-MAH增容体系的相区尺寸相对较大,PP相的结晶温度和结晶度明显降低,共混物只有冲击强度明显高于非增容体系,拉伸强度略低于非增容体系。     

Studies on polymer blend of nylon 6 and polypropylene or nylon 6 and polystyrene using the reaction of polymer

In the presence of maleic anhydride-grafted polypropylene, marked dispersibility of the polymer blend of isotactic polypropylene and nylon 6 was obtained. This appeared to be caused by the formation of a certain graft polymer between maleic anhydride in polypropylene and terminal amino groups of nylon 6. The same phenomenon was observed when polystyrene and nylon 6 were blended with styrene–methacrylic acid copolymer as the interpolymer. The existence of such a graft polymer was confirmed by solvent extraction, estimation of the amino group of nylon 6, and identification by differential scanning calorimetry. The physical properties, especially mechanical properties of nylon 6–polypropylene polymer blends, were remarkably improved with increase of maleic anhydride added to the polymer blend. On the other hand, the physical properties those of nylon 6–polystyrene polymer blends were very little improved even in the presence of good dispersibility.     

Barium sulfate–filled blends of polypropylene and polystyrene: Microstructure control and dynamic mechanical properties

The microstructure of filled blends consisting of a semicrystalline polypropylene homopolymer (PP) matrix and a polystyrene (PS) dispersed phase with barium sulfate (BaSO₄) filler can be controlled by an addition of maleic anhydride-grafted polypropylene (PP-g-MAH) or styrene-maleic anhydride copolymer (SMA). Scanning electron microscopy (SEM) and dynamic mechanical analysis (DMA) in the solid and melt states were the analytical tools used. The filler is occluded at the interface of the polymer phases in the filled blend without PP-g-MAH or SMA. The addition of BaSO₄ to the PP/PS blend results in a decrease in domain size of the minor polymer phase. The filler is occluded in the PP phase when PP-g-MAH is added, while SMA results in the occlusion of the barium sulfate filler in the PS phase. The results of the SEM and the DMA studies were correlated, with indications of a filler network structure with both the PP-g-MAH and SMA modifiers. The barium sulfate filler surface has a specific affinity to maleic anhydride copolymers. The BaSO₄ filler alone did not have a nucleation effect on the PP; however, in combination with PP-g-MAH, a clear nucleation effect was observed.     

Compatibility,adhesional interaction of components,impact strength,and rheological behavior of polycarbonate/polycarbonate‐siloxane block copolymer

Polycarbonate (PC) blended with a polymer‐modifier polycarbonate–polydimethylsiloxane (PC–PDMS) of polyblock structure having equal molar ratios of soft (PDMS) and hard (PC) blocks have been investigated. The kinetics of adhesional interaction in blends and the analysis of interphase interaction conducted by using the relaxation spectrometry showed that intensive interactions between phases can occur. At a concentration of the modifier ≤5 wt %, these effects can lead to a partial compatibility of the components. The phase separation comes to completion when PC–PDMS content reaches 7 to 10 wt %. Here the impact strength of the blends improves compared with homopolycarbonate; this factor becomes less sensitive to the notch pattern or surface defects. The micro‐heterogeneous blends would fail by the multiple crazing mechanism. The mode of temperature vs impact strength relationship depends on the concentration of the modifier. Low shearing rates applied to the PC blends containing 3 to 7 wt % of PC–PDMS results in a lower melt flow index compared with that for a neat PC. The blends were more sensitive to shearing stresses than the homopolycarbonate. Therefore, they have lower viscosity at a high shearing rate than PC. Introduction of PC–PDMS into PC did not change its thermal stability significantly. The modifier inhibited the chemical crosslinking of PC chains if the melt had been kept for a long period. The optimal mechanical properties combined with improved processability were found in blends containing 7 to 10 wt % of PC–PDMS. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 858–869, 2000     

Recycling of blends of acrylonitrile–butadiene–styrene (ABS) and polyamide

The aim of this work is to evaluate routes to upgrade recycled engineering plastics, especially mixed plastics with acrylonitrile–butadiene–styrene copolymers (ABS) as the major component. A core‐shell impact modifier was successfully used to improve the impact strength of blends of ABS and ABS/polycarbonate (PC) blends recycled from the automotive industry. However, the presence of other immiscible components like polyamide (PA), even in small amounts, can lead to a deterioration in the overall properties of the blends. A styrene–maleic anhydride (SMA) copolymer and other commercial polymer blends were used to promote the compatibilization of ABS and PA. The core‐shell impact modifier was again found to be an efficient additive with regard to the impact strength of the compatibilized ABS/PA blends. The results obtained with fresh material blends were quite promising. However, in blends of recycled ABS and glass‐fiber‐reinforced PA, the impact strength did not exhibit the desired behavior. The presence of poorly bonded glass fibers in the blend matrix was the probable reason for the poor impact strength compared with that of a blend of recycled ABS and mineral‐filled PA. Although functionalized triblock rubbers (SEBS–MA) can substantially enhance the impact strength of PA, they did not improve the impact strength of ABS/PA blends because the miscibility with ABS is poor. The possibilities of using commercial polymer blends to compatibilize otherwise incompatible polymer mixtures were also explored giving promising results. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2535–2543, 2002     

Impact toughness,viscoelastic behavior,and morphology of polypropylene–jute–viscose hybrid composites

In this investigation, we studied the impact toughness and viscoelastic behavior of polypropylene (PP)–jute composites. In this study, we used viscose fiber as an impact modifier and maleated PP as a compatibilizer. The toughness of the composites was studied with conventional Charpy and instrumental falling‐weight impact tests. The composites’ viscoelastic properties were studied with dynamic mechanical analysis. The results show that the incorporation of viscose fibers improved the impact strength and toughness to 134 and 65% compared to those of the PP–jute composites. The tan δ peak amplitude also increased with the addition of the impact modifier and indicated a greater degree of molecular mobility. The thermal stability of the composites was evaluated with thermogravimetric analysis. The addition of 2 wt % maleated polypropylene (MAPP) to the impact‐modified composite improved the impact strength and toughness to 144 and 93%, respectively. The fiber–matrix morphology of the fracture surface and the Fourier transform infrared spectra were also studied to ascertain the existence of the type of interfacial bonds. Microstructural analysis showed the retention of viscose fibers in the composites compared to the more separated jute fibers. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42981.     

Bamboo fiber-reinforced polypropylene composites: A study of the mechanical properties

A new type of bamboo fiber-reinforced polypropylene (PP) composite was prepared and its mechanical properties were tested. To enhance the adhesion between the bamboo fiber and the polypropylene matrix, maleic anhydride-grafted polypropylene (MAPP) was prepared and used as a compatibilizer for the composite. The maleic anhydride content of the MAPP was 0.5 wt %. It was found that with 24 wt % of such MAPP being used in the composite formulation, the mechanical properties of the composite such as the tensile modulus, the tensile strength, and the impact strength all increased significantly. The new composite has a tensile strength of 32–36 MPa and a tensile modulus of 5–6 GPa. Compared to the commercially available wood pulp board, the new material is lighter, water-resistant, cheaper, and more importantly has a tensile strength that is more than three times higher than that of the commercial product. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1891–1899, 1998     

Improved compatibility between polyamide and polypropylene by the use of maleic anhydride grafted SEBS

Blends containing equal weight fractions of polypropylene (PP) and polyamide (PA-6 and PA-6.6) and up to 25% of a compatibilizing thermoplastic elastomer, either polystyrene-block-poly(ethylene-stat-butylene)-block-polystyrene (SEBS) or SEBS modified by maleic anhydride (SEBS-MA), were prepared by melt mixing. In all these blends, PP formed the continuous matrix phase. Even at high concentrations, unmodified SEBS was found to be a poor compatibilizer, affecting mainly the properties of the matrix. The graft copolymer formed, by reaction between SEBS-MA and polyamide during melt mixing, strongly influenced the blend morphology, by forming an interphase, separating the PA phase domains from the matrix. The crystallization behaviour of PP indicated that full coverage required between 3% and 5% SEBS-MA at the intense mixing conditions used. Above this level, the total surface area of the polyamide domains seemed to increase in direct proportion to the concentration of SEBS-MA. The thickness of the interphase layer was estimated to be about 15 nm. At high concentrations of SEBS-MA, the PA domains agglomerated and formed extended structures held together by the interphase polymer. This was reflected by the stress–strain and rheological behaviour of the blends. In blends with PA domains of small volume, crystallization of PA was delayed. The rate of water absorption was very low in blends containing SEBS-MA, much lower than in corresponding blends containing SEBS.     

高性能木纤维增强聚丙烯复合材料的制备

采用双螺杆挤出机制备了木纤维（松木粉）增强聚丙烯（PP）复合材料，并对其力学性能及形态结构进行了研究。结果表明，用马来酸酐接枝PP（PP-g-MAH)作增容剂可有效地增加基体与木纤维之间的粘合作用，使木纤维增强PP复合材料的拉伸强度，弯曲强度和弯曲弹性碍都得到很大提高；在木纤维增强PP复合材料中加入三元乙丙橡胶（EPDM）进行增韧，可在高木纤维含量下使复合材料基本保持纯PP的力学性能。     

Novel approach for the preparation of a compatibilized blend of nylon 11 and polypropylene with polyhydroxybutyrate: Mechanical,thermal, and barrier properties

This article comprises of the interaction in the immiscible polymer system of nylon 11 (PA 11), polypropylene (PP), and polyhydroxybutyrate (PHB). Reactive compatibilization extrusion method with maleic anhydride-grafted polypropylene (PP-g-MA) is used to achieve compatibility within the polymer. To further improve the interaction of the blend at interphase, PHB was added as a dispersive phase in a concentration varying from 10 to 40% of the total batch. Addition of PHB motives the excellent dispersion of PP chain in PA 11 and assures the compatibility between the phases of PA 11 and PP-g-MA. The entire system of tertiary and binary phases was blended in a twin-screw extruder at different composition. The macro-optimal tensile strength, Young's modulus, bending strength, and notched impact strength of PA11/PP systems were found to be superior as compared to their noncompatibilized systems. The degradation temperature of the blends of PA11/PP and PA11/PHB/PP with and without compatibilizer was evaluated by thermogravimetric analysis (TGA). It was found that the high temperature of degradation was required for compatibilized ternary blend than that of the compatibilized binary blend. The distortion temperature of the systems was studied with the help of heat deflection temperature (HDT) and found to be advanced for blend having a higher concentration of the dispersed phase. Differential scanning calorimetry (DSC) was used to determine the % crystallinity, melting, and crystallization temperature of this system. Chemical resistance and barrier properties of the different compatibilized and noncompatibilized blends were studied. PHB dispersed phase with a reactive compatibilizer cause enhancement in chemical resistance and barrier properties of the blend. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48152.     

Plastic waste minimization: Compatibilization of polypropylene/polyamide 6 blends by polyalkenyl‐poly‐maleic‐anhydride‐based agents

The present article discloses the properties improvement in PP/PA 6 blends by new type experimental coupling additives. By the experimental agents especially the tensile properties could be improved. For example, the tensile strength and the elongation were 16.5 MPa and 4.4% without additive, which increased to 25.5, 20.1, 46.8 MPa and 8.1, 6.4, 8.6% in specimens containing polyalkenyl‐poly‐maleic‐anhydride‐amide, polyalkenyl‐poly‐maleic‐anhydride‐ester, and MA‐grafted‐low‐polymer additives, respectively. DSC curves shows that compatibilizers influenced thermal properties of the polymer blends and reveal affecting of crystalline phase formation process in the blends due to the compatibilization step. Additives A and B rather leads to influencing of PA crystallinities. According to the SEM and FTIR analysis well separated polypropylene and polyamide phases was observed in case of specimens absence of additives but only one well distributed phase by the applying of the synthetized coupling agents. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Zweiphasige Mischungen aus Polyamid 6 und Polyäthylen

Polymer blends of polyamide 6 and polyethylene are obtained by application of high shearing forces to the two component polymer melt. No formation of block and of graft copolymers occurs. The polymer blend consists of two separate and mutually incompatible phases of both components, determining its bulk properties. To improve the compatibility of both polymers, experiments were performed to graft polyamide 6 onto polyethylene. It could be shown that polyethylene modified with maleic anhydride was especially suited for this purpose. Polyamide 6 chains could be grafted onto this modified polyethylene by anionic polymerization. The mechanical properties of a mixture of the graft copolymer with polyamide 6 are significantly better than those of a mere polyamide-6-polyethylene blend. This improvement is attributed to a greater homogenity of the two phase mixture if the graft copolymer is added.     

Blend compatibilizers based on silane‐ and maleic anhydride–modified polyolefins

Polypropylene (PP)/polyamide blends were compatibilized with PP modified with vinylsilane or maleic anhydride and ethylene–propylene random (EPR) copolymer modified with maleic anhydride. The thermal behavior, mechanical properties, and morphology of the blends were investigated. Thermal analysis showed that the polyamide crystallization temperatures shifted downward with all compatibilizers, whereas its melting behavior did not change. On the other hand, polypropylene crystallization temperatures shifted upward in all cases, except for blends containing EPR modified with maleic anhydride. Tensile strength and elongation at break increased for blends compatibilized with modified PP. Blends containing up to 7% of EPR modified with maleic anhydride did not show good yield stresses. The morphology of the blends showed a finer dispersion of the polyamide minor phase in the PP matrix. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2492–2498, 2003     

Effect of coupling agent on polylactic acid/polypropylene and polylactic acid/polyamide 6 foam composites

The main part of polymer materials generated from fossil fuels do not degrade after completing their usage life and then begin to be waste in the environment. This situation has led to the emphasis on environmentally friendly, biodegradable, and bio-based polymers obtained from renewable sources as an alternative. In recent years, several studies are concentrated on especially lightweight and carbon dioxide (CO₂) emission limitations. In this work, the goal was to investigate at the same time environmentally friendly and lightweight polymer foam composites based on polylactic acid (PLA) polymer without lowering the performances of the materials. In this aim, polymer foam composites containing polypropylene (PP), polyamide 6 (PA6) and PLA were produced (PLA/PA6 (30:70) and PLA/PP (30:70)) with a chemical blowing agent (CBA) introduced at 1.5 wt.% to the polymer mixture. To improve the interpolymer compatibility and foaming activity maleic anhydride-grafted polylactic acid (PLA-g-MA) was utilized as coupling agent (CA) in different ratios (1, 3 and 5 wt.%). From the evaluation of the polymer mixtures in terms of their lightness, thermal and mechanical strength, the most appropriate CA ratios were determined as 1 wt.% for foamed PLA/PP (30:70) mixtures and 3 wt.% for foamed PLA/PA6 (30:70) mixtures.     

Polypropylene/polyamide 6/polyethylene-octene elastomer blends. Part 2: volume dilatation during plastic deformation under uniaxial tension

Plastic deformation upon stretching was investigated in ternary blends of polypropylene, polyamide 6 and maleic anhydride-grafted polyethylene-octene elastomer (PP/PA6/POE). A novel video-controlled tensile testing method was utilized, which allows recording simultaneously axial strain, axial stress and volume strain while axial strain-rate is regulated at a constant value even after necking has begun. Increasing the alloying content modifies drastically the original stress-strain properties of PP: yield softening is suppressed and strain hardening is increased. As for the volume strain, which is representative of the overall cavitation process, it is found to decrease with increasing alloying content (apart from a small increase for low alloying content). This unexpected result indicates that the finely dispersed cavities nucleated under tension at the POE interphase of PA6 particles and at isolated POE particles favor the profuse development of plastic shear bands in the PP matrix. As such, it can be considered as an experimental evidence of the synergistic effect of cavitation and shear banding in a structural polymer.     

The effects of the location of organoclay on the structure and mechanical properties of compatibilized polypropylene/polyamide‐12 ternary nanocomposites

Ternary nanocomposites (NCs) were obtained by melt‐mixing maleic anhydride‐modified polypropylene (gPP) with previously prepared polyamide‐12 (PA12)/organically modified montmorillonite (OMMT) NCs. During melt‐mixing, OMMT migrated from the PA12 phase to the gPP/PA12 interphase. Moreover, a critical concentration of OMMT was found to saturate the interphase and, at higher contents, the excess OMMT migrated to the gPP matrix. When compared with the unfilled gPP/PA12 blends, the addition of OMMT caused a change in the microstructure. The average size of the PA12 dispersed particles in the NCs was found to be independent of the OMMT content. At OMMT contents below the critical concentration, that is, when the OMMT located at the interphase, Young's modulus remained practically unchanged and the ductile nature of the ternary NCs maintained. However, at higher OMMT contents, Young's modulus increased linearly and the NCs became brittle, due to the presence of OMMT in the gPP matrix. POLYM. ENG. SCI., 58:830–838, 2018. © 2017 Society of Plastics Engineers