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1.
In order to develop excellent comprehensive mechanical strength and stability in high-density polyethylene (HDPE)/wood fiber (WF) composites, polyamide 6 (PA 6), and WF modified by environmental-friendly high temperature vapor (WF-HTV) were utilized to reinforce the compound system. The properties relating to interfacial compatibility in HDPE/WF-HTV composites were characterized and evaluated by electron universal mechanical instrument, water absorption testing, thermogravimetry, scanning electron microscope, Fourier transfer infrared spectroscopy, and differential scanning calorimetry. The results reveal that this novel compounding system can engender a synergistic effect for interfacial interactions among PA 6, HDPE, and WF-HTV only when the ratio of HDPE to PA 6 is at an optimum level (HDPE:PA 6 = 6:4). The maximum values for flexural strength, modulus, tensile strength, and impact strength can be increased by 82.05, 64.08, 93.47, and 120.45%, respectively, compared with those of HDPE/WF-HTV composites. Additionally, maximum decomposition temperatures for the first and second thermal degradation stages can be increased by 7.17and 8.99 °C, respectively. Water absorption can be effectively controlled at a relatively low level (approximately 1.50%). © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47984.  相似文献   

2.
In this article, high density polyethylene/styrene‐ethylene‐butylene‐styrene block copolymer blends (HDPE/SEBS) grafted by maleic anhydride (HDPE/SEBS‐g‐MAH), which is an effective compatibilizer for HDPE/wood flour composites was prepared by means of torque rheometer with different contents of maleic anhydride (MAH). The experimental results indicated that MAH indeed grafted on HDPE/SEBS by FTIR analysis and the torque increased with increasing the content of maleic anhydride and dicumyl peroxide (DCP). Styrene may increase the graft reaction rate of MAH and HDPE/SEBS. When HDPE/SEBS MAH was added to HDPE/wood flour composites, tensile strength and flexural strength of composites can reach 25.9 and 34.8 MPa in comparison of 16.5 and 23.8 MPa (without HDPE/SEBS‐g‐MAH), increasing by 157 and 146%, respectively. Due to incorporation of thermoplastic elastomer in HDPE/SEBS‐g‐MAH, the Notched Izod impact strength reached 5.08 kJ m?2, increasing by 145% in comparison of system without compatibilizer. That HDPE/SEBS‐g‐MAH improved the compatibility was also conformed by dynamic mechanical measurement. Scanning electron micrographs provided evidence for strong adhesion between wood flour and HDPE matrix with addition of HDPE/SEBS‐g‐MAH. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007  相似文献   

3.
Chemical modification of lignocellulosic fibers can improve interfacial adhesion and dimensionally stabilize the resulting plastic composites. This study examined the rheological properties of wood flour/high density polyethylene (HDPE) melts after poplar wood flour was modified with glutaraldehyde (GA, mainly cell wall cross‐linking) and 1,3‐dimethylol‐4,5‐dihydroxyethyleneurea (DMDHEU, mainly poly‐condensation). Results show improvement in both the dispersibility of treated wood flour in the HDPE and its interfacial compatibility. Treatment with GA decreased melt viscosity, moduli, and shear stress as evidenced by rheometry. However, the modifying effects of DMDHEU were not observed, which was mainly due to reduced HDPE content. This study indicates that chemical modification of wood flour is a promising approach to improve the processability of highly filled wood thermoplastic composites via extrusion/injection molding processing. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41200.  相似文献   

4.
This article discusses the methods of interface modification of composites based on raw wood flakes and high‐density polyethylene (HDPE) and the effects of these modifications on composite properties. An HDPE matrix was modified by a reaction with maleic anhydride (MA) in a twin‐screw extruder and then compounded with wood flakes to produce wood–polyethylene composites. Wood flakes were modified by a reaction with a silane coupling agent in an aqueous medium before being compounded with HDPE to produce silane‐modified WPCs. Differential scanning calorimetry and Fourier transform infrared spectroscopy data provide evidence for the existence of a polyethylene (PE)–silane‐grafted wood structure, which acts as a compatibilizer for wood flakes and PE. The results of MA‐modified composites indicate that some maleated HDPE is reacting with wood through esterification to form a compatibilizer for wood flakes and HDPE. Significant improvements in tensile strength, ductility, and Izod impact strength were obtained. Scanning electron micrographs provide evidence for strong interactions between the wood flakes and the matrix agent. The results indicate that 1–2 wt % MA modification on HDPE and 1–3 wt % silane treatment on wood flakes provide WPCs with the optimum properties. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2505–2521, 2002  相似文献   

5.
Abstract

The main objective of this study was to find out if there is any significant correlation between physical properties and interfacial bonding of interphases in wood–plastic composites. To this end, high-density polyethylene (HDPE), mixture of 3% maleic anhydride grafted polyethylene (MAPE) and HDPE (coded as MHDPE) and polylactic acid (PLA) were separately interacted with veneers to identify factors underlying interfaces. Plastics were first melted at 180?°C and dispensed on wood surfaces so that the contact angle (CA) could be directly measured. Wood sanding moderately decreased the CAs of plastics in order of PLA, MHDPE, and HDPE. The treatment of veneers with MAPE comprehensively improved wetting, as the CA of HDPE was significantly reduced on the wood surface after the treatment. Thereafter, the interfacial shear strengths (IFSS) of the wood–polymer interface were determined using the automated bonding evaluation system. PLA had the highest IFSS both for unsanded and sanded veneers. Comparing both parts of this research finally revealed that applying sanding or/and MAPE treatments resulted in lower surface free energy and higher IFSS at the wood–polymer interface. However, our observations support the idea that, at higher temperatures, wetting of composites is mainly influenced by polymer properties rather than interfacial tension at the wood–polymer interface.  相似文献   

6.
Fibers of high density polyethylene (HDPE)/organically modified hydrotalcite (LDH) were produced by melt intercalation in a two‐step process consisting of twin‐screw extrusion and hot drawing. The optimum drawing temperature was 125°C at which the draw ratios up to 20 could be achieved. XRD analysis revealed intercalation with a high degree of exfoliation for the composites with 1–2% of LDH. Higher thermal stability of nanofilled fibers was confirmed by TGA analysis. DSC data indicated that dispersed LDH particles act as a nucleating agent. Crystallization kinetics of the HDPE matrix in the composite fibers is characterized by two transition temperatures, that is, for Regimes I/II at 123°C and for Regimes II/III ranging between 114–119°C as a function of the nanocomposite composition. Fibers with 1–2% of LDH show for the drawing ratios up to 15 a higher elastic modulus, 9.0–9.3 GPa (with respect to 8.0 GPa of the neat HDPE), maintain tensile strength of 0.8 GPa and deformation at break of 20–25%. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40277.  相似文献   

7.
Graphene nanoplatelets coated by polyaniline (GNP@PANI) and ethylene–vinyl acetate (EVA) copolymer–high‐density polyethylene (HDPE) were used for the first time to prepare high‐performance antistatic composites through an effective method that combined solution mixing and melt blending. GNP@PANI nanocomposites were fabricated by in situ polymerization to improve the dispersion of graphene nanoplatelets (GNPs) in the EVA–HDPE matrix and the compatibility between the GNPs and the EVA–HDPE matrix. The GNP@PANI nanocomposites and EVA were first prepared as a premix through solution mixing, and then, the premix and HDPE were prepared as highly antistatic composites through melt blending. The dispersion of the GNPs in the EVA–HDPE matrix and the compatibility between the GNPs and the EVA–HDPE matrix were confirmed by field emission scanning electron microscopy and transmission electron microscopy observations. The GNP@PANI–EVA–HDPE composites met the requirements for antistatic materials when the content of the GNP@PANI nanocomposites was 5 wt % with only about 1 wt % GNPs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45303.  相似文献   

8.
In this study, polypropylene random copolymer (PPR) composites were prepared by the addition of either three kinds of thermoplastic rubber (TPR) modifiers (types 2088A, 2095, and 2096) or an ethylene–octene copolymer (POE)/high‐density polyethylene (HDPE; 2 :1 w/w) blend. Differential scanning calorimetry, wide‐angle X‐ray diffraction, and dynamic mechanical analysis were used to characterize the crystallization behaviors and dynamic mechanical properties of the PPR composites. The results indicated that PPR/POE/HDPE and PPR/TPR2088A had better comprehensive mechanical properties, especially the low‐temperature toughness among all of the samples. The obtained PPR/POE/HDPE blends showed a high toughness and good stiffness in the temperature interval from ?10 to 23°C with the addition of only 10 wt % POE/HDPE. When the temperature continued to fall below ?10°C, the PPR/TPR2088A composites exhibited a better impact toughness without a loss of too much stiffness. The good low‐temperature toughness of those two composites was attributed to both the decrease in the crystallinity and the uniform dispersion, obvious interfacial adhesion, and cavitation ability of POE/HDPE and TPR2088A in the PPR matrix. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42960.  相似文献   

9.
To quantitatively evaluate the effect of maleic anhydride grafted polypropylene (MAPP) as a coupling agent on interfacial compatibility between wood and polymer in wood/polypropylene (PP) composite, the dielectric constant and dielectric loss factor were measured for poplar (Populus tomentasa Carr.) wood flour/polypropylene (PP) composites prepared with six MAPP loading levels (0.5, 1.0, 1.5, 2.0, 4.0, and 8.0%), and the Cole–Cole plots, the dielectric relaxation strength, the distribution of relaxation time and the activation thermodynamic quantities of the dielectric relaxation based on the reorientation of the methylol groups (CH2OH) in the amorphous region of wood cell wall were further analyzed. The results showed that the dielectric relaxation strength decreased with the MAPP loading and dropped to the lowest at MAPP loading of 2.0%, after which it kept almost constant. It suggested that the internal bonding between wood and PP molecules was the strongest at 2.0% MAPP, therefore the reorientation of the methylol groups in wood became very difficult under the strong hindrance from the long‐chained PP molecules and the physical or/and chemical bonds between MAPP, wood flour, and PP in the composites. The activation free energy ΔE could be served as the indicator to quantitatively evaluate the effect of MAPP on interfacial compatibility of the wood/PP composites. ΔE of 2.0% MAPP modified composites showed the maximal value among all the tested conditions, which was 33.52 kJ mol−1; while the values for 1.5 and 4.0% MAPP modified were 23.35 and 21.75 kJ mol−1. Therefore, excessive MAPP was not beneficial to improve the internal compatibility of wood/PP composites, but had negative effect. POLYM. COMPOS., 35:489–494, 2014. © 2013 Society of Plastics Engineers  相似文献   

10.
This study is aimed at utilizing nutraceutical industrial waste and reducing carbon footprints of plastics. Eco‐friendly “green composites” of high density polyethylene (HDPE) were fabricated using coleus spent (CS)—a nutraceutical industrial waste as reinforcing filler and maleic anhydride‐graft‐polyethylene (MA‐g‐PE) as compatibilizer. Composites were fabricated with 5, 10, 15, and 20% (w/w) of CS by extrusion method. The fabricated HDPE/CS composites were evaluated for mechanical and thermal behavior. A slight improvement of about 5% in tensile strength and marked improvement of about 25% in tensile modulus for 20 wt % CS filled HDPE composites was noticed. The effect of CS content on rheological behavior was also studied. Thermal characteristics were performed using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). TGA thermogram indicated increased thermal stability of CS‐filled composites. From TGA curves the thermal degradation kinetic parameters of the composites have been calculated using Broido's method. The enthalpy of melting (ΔHm) obtained from DSC curves was reduced with increase in CS content in HDPE matrix, due to decrease in HDPE content in composite systems. An increase in CS loading increased the water absorption behavior of the composites slightly. Morphological behavior of cryo‐fractured composites has been studied using scanning electron microscopy. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

11.
The melt rheological studies on HDPE/TWF (teak wood flour) composites were studied at (volume fraction) Φf = 0.00?0.32 and at 180°C, 190°C and 200°C. Viscosity of HDPE/TWF composites increases with Φf while decreases with increase in temperature. Addition of coupling agent, maleic anhydride grafted HDPE (HDPE-g-MAH) enhances viscosity as compared to the corresponding HDPE/TWF. This was attributed to increase in interaction between TWF and HDPE by HDPE-g-MAH which in turn stiffens the system. The power law coefficient, n, decreases with increase in Φf and increase in temperature and lower for HDPE/TWF/HDPE-g-MAH composites as compared to HDPE/TWF composites. The consistency index increases with increase in Φf and were higher for HDPE/TWF/HDPE-g-MAH.  相似文献   

12.
The disposal of paper mill sludge (PMS) is a difficult environmental problem. Thus, PMS has been used as a substitute for wood fiber (WF) to reinforce high‐density polyethylene (HDPE). In this study, we compared PMS–WF–HDPE composites with composites without PMS after water immersion and thermal treatment. Water immersion and thermal treatment were conducted at 25 and 70°C, respectively. The results show that the composites with PMS absorbed less water but lost more of their original flexural properties after immersion; thereby, their strength was compromised. These reduced mechanical properties could be partially restored after redrying. After the thermotreatment, the composites with added PMS lost their weight and flexural properties, whereas the composites without PMS gained flexural strength. The results show that the thermotreatment improved the impact strength of the composites when no more than one‐third of WF was replaced with PMS. Fourier transform infrared spectroscopy and energy‐dispersive X‐ray energy‐dispersive spectroscopy showed that the wood index of the PMS composite decreased more than the index of the non‐PMS composite, whereas the carbonyl index increased more. However, the PMS composite showed a lower increase in the total oxygen/carbon weight ratio. This study suggested that limited amounts of WF could be substituted with PMS to reinforce HDPE. However, WF–PMS–HDPE composites should not be used in hot, humid environments for long periods. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41655.  相似文献   

13.
When natural fiber‐thermoplastic composites are used in long‐term loading applications, investigating creep behavior is essential. The creep behavior of high‐density polyethylene (HDPE)‐based composites reinforced with four sizes of wood fibers (WFs) (120–80, 80–40, 40–20, and 20–10 mesh) was investigated. The instantaneous deformation and creep strain of all WF/HDPE composites increased at a fixed loading level when the temperature was increased incrementally from 25 to 85°C. At a constant loading level, composites containing the larger‐sized WFs had better creep resistance than those containing smaller‐sized fibers at all measured temperatures. The creep properties of composites with smaller‐sized WFs were more temperature‐dependent than those with larger‐sized WFs. Two creep models (Burger's model and Findley's power law model) were used to fit the measured creep data. A time–temperature superposition principle calculation was attempted for long‐term creep prediction. The Findley model fitted the composite creep curves better than the four‐element Burger's model. From the predicted creep response of the WF/HDPE composites, two groups of small fibers (120–80 and 80–40 mesh) had the lowest creep resistance over long periods of time at the reference temperature of 25°C. The largest WFs (10–20 mesh) provided the best composite creep resistance. POLYM. ENG. SCI., 55:693–700, 2015. © 2014 Society of Plastics Engineers  相似文献   

14.
Effect of temperature on hygroscopic thickness swelling rate of lignocellolusic fillers/HDPE (high density polyethylene) composites was investigated. The composites were manufactured using a dry blend/hot press method. In this method, powder of plastic and dried powder of lignocellolusic material were mixed in high‐speed mixer and then the mixed powder were pressed at 190°C. Lignocellolusic fillers/HDPE composites panels were made from virgin and recycled HDPE (as plastic) and wood sawdust and flour of rice hull (as filler) at 60% by weight filler loadings. Nominal density and dimensions of the panels were 1 g/cm3 and 35 × 35 × 1 cm3, respectively. Thickness swelling rate of manufactured wood plastic composites (WPCs) were evaluated by immersing them in water at 20, 40, and 60°C for reaching a certain value where no more thickness was swelled. A swelling model developed by Shi and Gardner [Compos. A, 37 , 1276 (2006)] was used to study the thickness swelling process of WPCs, from which the parameter, swelling rate parameter, can be used to quantify the swelling rate. The results indicated that temperature has a significant effect on the swelling rate. The swelling rate increased as the temperature increased. The swelling model provided a good predictor of the hygroscopic swelling process of WPCs immersed in water at various temperatures. From the activation energy values calculated from the Arrhenius plots, the temperature had less effect on the thickness swelling rate for the composites including wood sawdust compared with the rice hull as filler and the composites including recycled compared with the virgin HDPE as plastic. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers  相似文献   

15.
Pyrolyzed oil shale (POS) obtained from the pyrolysis of bituminous rock was burned in a normal atmosphere (POSB) to remove the organic phase and then used as a filler in poly(ethylene‐co‐vinyl alcohol) (EVAL). The effects of vinyl alcohol content, POSB particle size, and POSB concentration on the composite were investigated through measurement of mechanical properties. Composites were prepared in a rotor mixer at 180°C. Stress–strain plots of compression‐molded composites showed synergic behavior of the mechanical properties with low concentrations (1–5 wt %) of POSB, regardless of particle size or type of EVAL. Such behavior suggests close packing and strong interactions between inorganic filler and polymer, with the effects reinforced by the mechanical properties. It was observed that the absence of the organic phase in the modified material improved the mechanical properties of the composites. Increasing the vinyl alcohol content improved the compatibility between polymer and filler in the EVAL/POS but did not affect the compatibility in EVAL/POSB composites. The relationship of mechanical and morphological behavior in the EVAL/POS and EVAL/POSB composites indicated that different factors were at play to explain the compatibility between the EVAL and the inorganic phase. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1859–1864, 2006  相似文献   

16.
High‐density polyethylene/wood flour (HDPE/WF) composites were prepared by a twin‐screw extruder. The effects of WF, silane coupling agents, polymer compatibilizers, and their content on the comprehensive properties of the WF/HDPE composites have been studied in detail, including the mechanical, thermal, and rheological properties and microstructure. The results showed that both silane coupling agents and polymer compatibilizers could improve the interfacial adhesion between WF and HDPE, and further improve the properties of WF/HDPE composites, especially with AX8900 as a compatibilizer giving higher impact strength, and with HDPE‐g‐MAH as a compatibilizer giving the best tensile and flexural properties. The resultant composite has higher strength (tensile strength = 51.03 MPa) and better heat deflection temperature (63.1°C). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   

17.
High density polyethylene/organo‐modified montmorillonite composites whit various concentrations of maleic anhydride grafted high density polyethylene (MA‐g‐HDPE) as compatibilizer (5–20 wt %) have been prepared by melt process. The extruded composite powders are applied on the treated steel surfaces using spray electrostatic powder technique, followed by oven curing at various temperatures (180°C–220°C) and times (15–45 min). The surface uniformity of produced coating films is studied by scanning electron microscopy. Comparison of micrographs of the coatings shows the composite coating films are measured using standard methods. The uniformity, adhesion, and bending strength of the coating films are compared to select high performance coatings. The results indicate that the presence of 15 wt % MA‐g‐HDPE in the coatings shows the highest properties (adhesion and bending strength) and more surface uniformity. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40926.  相似文献   

18.
Composites of high density polyethylene (HDPE) with the reinforcements of glass fiber (GF) and wood flour (WF) have been studied in this work. High‐density polyethylene‐grafted maleic hydride (HDPE‐g‐MAH) was used as a compatibilizer. In particular, the effect of GF, WF, and HDPE‐g‐MAH on the overall properties of GF/WF/HDPE composites (GWPCs in short form) was systematically studied. The results indicate that HDPE‐g‐MAH as a compatibilizer can effectively promote the interfacial adhesion between GF/WF and HDPE. By the incorporations of GF/WF, the heat deflection temperature can reach above 120°C, and the water absorption can be below 0.7%, also the tensile strength, flexural strength, and impact strength of GWPCs can surpass 55.2 Mpa, 69.4 Mpa, and 11.1 KJ/m2, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

19.
The nonisothermal crystallization behavior and melting characteristics of high‐density polyethylene (HDPE) in HDPE/teak wood flour (TWF) composites have been studied by differential scanning calorimetry (DSC) and wide angle X‐ray diffraction (WAXD) methods. Composite formulations of HDPE/TWF were prepared by varying the volume fraction (?f) of TWF (filler) from 0 to 0.32. Various crystallization parameters evaluated from the DSC exotherms were used to study the nonisothermal crystallization behavior. The melting temperature (Tm) and crystallization temperature (Tp) of the composites were slightly higher than those of the neat HDPE. The enthalpy of melting and crystallization (%) decrease with increase in the filler content. Because the nonpolar polymer HDPE and polar TWF are incompatible, to enhance the phase interaction maleic anhydride grafted HDPE (HDPE‐g‐MAH) was used as a coupling agent. A shift in the crystallization and melting peak temperatures toward the higher temperature side and broadening of the crystallization peak (increased crystallite size distribution) were observed whereas crystallinity of HDPE declines with increase in ?f in both DSC and WAXD. Linear correlations were obtained between crystallization parameters and tensile and impact strength. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   

20.
Magnesium hydroxide (MH) was modified with triethoxysilane and polymethyl–vinyl silicone rubber and used to prepare flame-retardant oil-extended styrene–ethylene–butadiene–styrene (O-SEBS)–polypropylene (PP) composites. The water contact angle of modified magnesium hydroxide (MMH) reached 141°; this indicated that MMH possessed excellent hydrophobic properties. The samples (1.6 mm) passed the UL-94 V-0 rating during vertical burning tests when the loading amount of MH or MMH was 70 wt %. This indicated the modification did not decrease the flame-retardant properties of MH. The tensile strength and elongation at break values of the MMH–O-SEBS–PP composites increased by 20.4 and 88.9%, respectively, compared with those of the MH–O-SEBS–PP composites. The modification of MH enhanced the interfacial compatibility between the flame retardant and the matrix; thus, the mechanical performance was enhanced. Moreover, MMH was scarcely extracted after water treatment for 168 h at 70 °C. As a result, the mechanical properties and flame retardancy of the MMH–O-SEBS–PP composites were well maintained after the water treatment. The modification of the MH endowed the O-SEBS–PP composites with an excellent compatibility and water-resistant performance. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47129.  相似文献   

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