Preparation and properties of biodegradable poly(propylene carbonate)/starch composites

Biodegradable composites of poly(propylene carbonate) (PPC) reinforced with unmodified cornstarch were compounded in a batch mixer followed by compression molding. The effects of reinforcement on the morphology, static and dynamic mechanical properties, as well as thermal properties of PPC/starch composites, were investigated. Tensile tests showed that incorporation of starch improves the stiffness and tensile strength of composites significantly. Scanning electron microscopic examination revealed the existence of good interfacial adhesion between the fillers and PPC matrix. Moreover, experimental results indicated that the starch addition leads to a significant improvement in the thermal stability of the composites. This paper demonstrates that the incorporation of low‐cost and biodegradable cornstarch into PPC provided a practical way to produce completely biodegradable and cost‐competitive composites with good mechanical properties. Polym. Eng. Sci. 44:2134–2140, 2004. © 2004 Society of Plastics Engineers.     

Improving the thermal and mechanical properties of poly(propylene carbonate) by incorporating functionalized graphite oxide

Poly(propylene carbonate) (PPC) is a new biodegradable aliphatic polycarbonate. However, the poor thermal stability, low glass transition temperatures (T_g), and relatively low mechanical property have limited its applications. To improve the thermal and mechanical properties of PPC, functionalized graphite oxide (MGO) was synthesized and mixed with PPC by a solution intercalation method to produce MGO/PPC composites. A uniform structure of MGO/PPC composites was confirmed by X‐ray diffraction and scanning electron microscope. The thermal and mechanical properties of MGO/PPC composites were investigated by thermal gravimetric analysis, differential scanning calorimetric, dynamic mechanical analysis, and electronic tensile tester. Due to the nanometer‐sized dispersion of layered graphite in polymer matrix, MGO/PPC composites exhibit improved thermal and mechanical properties than pure PPC. When the MGO content is 3.0 wt %, the MGO/PPC composites shows the best thermal and mechanical properties. These results indicate that nanocomposition is an efficient and convenient method to improve the properties of PPC. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Comparative study on the effect of manchurian ash and larch wood flour on mechanical property,morphology, and rheology of HDPE/wood flour composites

Effects of wood flour species and polyethylene grafted with maleic anhydride (MA‐PE) on mechanical properties and morphology and torque rheology of high density polyethylene (HDPE)/wood flour composites have been comparatively investigated. The results demonstrated that without compatbilizer, wood flour species exhibited little influence on mechanical properties. In the presence of MA‐PE, the mechanical properties were obviously increased. On the basis of the mechanical property data obtained from wood flour extracted by different methods, the extractant was an important factor affecting the mechanical properties. Manchurian ash and larch wood flours extracted by hot water presented almost the same mechanical properties, and larch wood flour was the most beneficial to enhance the mechanical properties. The scanning electron microscopy (SEM) and the atomic force microscopy (AFM) further confirmed that interfacial adhesion and dispersion of manchurian ash wood flour in composites were effectively improved by MA‐PE. The torque results demonstrated that the chemical reactions of maleic anhydride groups on MA‐PE with hydroxyl on cellulose in wood flour probably took place due to the increase of the equilibrium torque and the appearance of the torque peak, and larch wood flour was more beneficial to prepare the composites containing the higher wood flour content. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effects of wood flour and chitosan on mechanical,chemical, and thermal properties of polylactide

Composites of polylactide (PLA, 100–60 wt%) and wood flour (0–40 wt%) were prepared to assess the effects of wood filler content on the mechanical, chemical, thermal, and morphological properties of the composites. The polysaccharide chitosan (0–10 wt%) was added as a potential coupling agent for the PLA‐wood flour composites. Addition of wood flour significantly increased the flexural modulus and the storage modulus of PLA‐wood flour composite, but neither the wood flour nor chitosan had an effect on the glass transition temperature (T_g). Fourier transform infrared spectra did not show any evidence of covalent bonding, but chitosan at the interface between wood and PLA is thought to have formed hydrogen bonds to PLA‐carbonyl groups. SEM images of fracture surfaces showed that fiber breakage was far more common than fiber pullout in the composites. No evidence of discrete chitosan domains was seen in SEM micrographs. When added at up to 10 wt% (based on wood flour mass), chitosan showed no significant effect on the mechanical, chemical, or thermal properties of the composites, with property changes depending on wood flour content only. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers.     

Effect of extractives on the performance properties of wood flour‐polypropylene composites

In this study, the effects of extractives in wood flour on the physicomechanical properties of wood flour‐polypropylene (PP) composites have been investigated. Three different solvents, hot‐water (HW), 1% NaOH (AL), and dichloromethane (DM), were used to remove extractives in both poplar and eucalypt wood flour. The obtained results showed that mechanical properties of the composites were moderately enhanced on using extractive‐free lignocellulosic materials in both the wood types. A large increase in the strength of eucalyptus flour‐PP composites was observed upon the removal of extractives from eucalyptus flour. Unlike the mechanical properties, no improvement in the water absorption and thickness swelling was observed for any type of extracted‐free samples. The thermal degradation behavior of the composites showed that in both cases, the degradation temperatures shifted to higher values after removing the extractives. In general, the removal of AL solubles was more effective in its improvement of the physicomechanical properties than the removal of HW and DM extractives. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Thermal and mechanical properties of wood flour–polystyrene blends from postconsumer plastic waste

Polystyrene (PS) from packing materials and plastic cups was reinforced with 30 and 50% wood flour through a blending process with and without a commercial compatibilizing agent. The processability of the pure recycled polystyrene (rPS) and wood–rPS composites was studied in terms of the torque of the mixing process; this was then compared with that of a commercial virgin multipurpose PS. The physical and mechanical properties were compared with those of the virgin PS reinforced with 30 and 50% wood flour. The results show that the mechanical properties of the pure and reinforced rPS did not decrease with respect to the virgin PS, and in terms of the impact strength, the rPS was superior to the virgin plastic. The mechanical properties were not affected by the commercial compatibilizing agent, but the torque of the blends was significantly lower with the compatibilizer. Differential scanning calorimetry (DSC) and dynamic mechanical analysis were used to study the glass‐transition temperature (T_g) of both the pure virgin PS and pure rPS and the wood flour–PS composites. The T_g values of the rPS and wood–rPS composites were higher than those of the virgin PS and wood–virgin PS composites. The use of rPS increased the stiffness and flexural modulus of the composites. Thermogravimetric analysis revealed that the thermal stability of rPS and its composites was slightly greater than that of the virgin PS and its composites. These results suggest that postconsumer PS can be used to obtain composite materials with good mechanical and thermal properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effects of crosslinking on the mechanical properties and biodegradability of soybean protein‐based composites

A green composite with good mechanical properties and acceptable biodegradability was developed using wood flour and soybean protein that was modified by thermal‐caustic degradation and chemical crosslinking with glyoxal and polyisocyanate (PMDI). Fourier transform infrared (FTIR) spectroscopy and scanning electron microscope (SEM) in combination with the traditional evaluations were employed to investigate the structure, morphology, and properties of the crosslinked soybean protein and the crosslinking‐modified wood/soybean protein composites to understand the effects of the crosslinker species on the mechanical properties, water resistance, and microbial biodegradation of soybean protein‐wood flour composites. The results indicated that the chemical crosslinking modification could improve the mechanical properties and water resistance but decrease the biodegradability of the wood/protein composite to a certain extent. Both glyoxal and PMDI alone as crosslinkers could not perfectly modify the soybean protein because of the high reactivity of PMDI and low crosslinking reactivity of glyoxal. The incorporation of glyoxal with PMDI could result in the desired crosslinking efficiency and good interfacial adhesion by compromising the advantages and disadvantages of glyoxal or PMDI alone as crosslinkers, which balanced the performances of the wood flour/soybean protein composite. The preferable combination crosslinker was composed of 50 wt % glyoxal and 50 wt % PMDI. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41387.     

Tensile properties,morphology, and thermal behavior of PVC composites containing pine flour and bamboo flour

Composites of unplasticized poly(vinyl chloride) (PVC) blended with bamboo flour and pine flour, respectively, were prepared in a batch mixer followed by compression molding. The effects of wood flour fillers on the morphology, static mechanical properties, and thermal properties of the composites were investigated. Compared with neat PVC resin, the introduction of both bamboo flour and pine flour significantly improved the stiffness of the composites, while decreasing the tensile strength to some extent. Tensile tests showed that pine flour–filled composites exhibited better mechanical properties than those filled with bamboo flour with the same particle size at the same loading level. Scanning electron microscopic examination revealed good dispersion and alignment tendency of short pine fiber within the composites at a lower loading level. Moreover, experimental results indicated that both bamboo flour and pine flour additions showed no obviously adverse effect on the thermal stabilities of these composites. Based on the comprehensive properties, these composites meet the need of woodlike material for use as wood structures. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1804–1811, 2004     

Study on PVC composites containing Eugenia jambolana wood flour

This article describes the properties of composites using unplasticized PVC matrix and wood flour (obtained by crushing the bark of Eugenia jambolana) as filler. Composites were prepared by mixing PVC with varying amounts of wood flour (ranging from 10–40 phr; having particle sizes of 100–150 μm and <50μm) using two‐roll mill followed by compression molding. The effect of wood flour content and its particle size on the properties, i.e., mechanical, dynamic mechanical, and thermal was evaluated. Tensile strength, impact strength, and % elongation at break decreased with increasing amounts of wood flour. Stiffness of the composites (as determined by storage modulus) increased with increasing amounts of the filler. Modulus increased significantly when wood flour having particle size <50 μm was used. Morphological characterization (SEM) showed a uniform distribution of wood flour in the composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Properties of glycerin‐thermally modified wood flour/polypropylene composites

This study aimed to investigate the combination effect of glycerin treatment and thermal modification of wood flour on the physical, mechanical, thermal dynamic mechanical properties of wood flour/polypropylene (PP) composite. The morphological aspect was also investigated. The wood flour was first impregnated in the aqueous solution of glycerin, followed by heat treatment at 200°C for 1 h. Then the unmodified or modified wood flour was blended with PP at a weight ratio of 4:6 to prepare composites. Moisture adsorption experiment and X‐ray photoelectron spectroscopy analysis of wood flour demonstrated that the hygroscopicity and the free surface hydroxyl groups of wood flour decreased after glycerin‐thermal modification. Thickness swelling of the 10% wt glycerin‐thermally modified wood flour/PP composite was reduced by 42.8% after 96 h immersion as compared to unmodified control. Evaluation of mechanical properties in impact and flexure modes indicated that glycerin treatment alone had no significant effect, but the combination of glycerin and thermal treatment slightly decreased the strength, with the exception of 10% glycerin and heat modified sample. Dynamic mechanical analysis and scanning electron microscope illustrated the improved interfacial bonding between PP and wood flour modified by 10% glycerin and heat treatment. POLYM. COMPOS., 35:201–207, 2014. © 2013 Society of Plastics Engineers     

Reinforcement of rigid PVC/wood‐flour composites with multi‐walled carbon nanotubes

Multi‐walled carbon nanotubes (CNT) were compounded with PVC by a melt blending process based on fusion behaviors of PVC. The effects of CNT content on the flexural and tensile properies of the PVC/CNT composites were evaluated in order to optimize the CNT content. The optimized CNT‐reinforced PVC was used as a matrix in the manufacture of wood‐plastic composites. Flexural, electrical, and thermal properties of the PVC/wood‐flour composites were evaluated as a function of matrix type (nonreinforced vs. CNT‐reinforced). The experimental results indicated that rigid PVC/wood‐flour composites with properties similar to those of solid wood can be made by using CNT‐reinforced PVC as a matrix. The CNT‐reinforced PVC did not influence the electrical and thermal conductivity of the PVC/wood‐flour composites. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers.     

Effect of the processing techniques on the properties of ecocomposites based on vegetable oil‐derived Mater‐Bi® and wood flour

Polymer composites based on biodegradable polymers and natural‐organic fillers are becoming more and more important because of their interesting properties in terms of environmental impact, manufacturing cost, and esthetic features. In particular, the use of biodegradable polymer matrices allows obtaining a full biodegradability. One of the most interesting biodegradable polymer families is the Mater‐Bi® one. In this work, we investigated the processability, the influence of different processing techniques, and the influence of the filler particle size on the properties of Mater‐Bi/wood flour composites. Injection molding caused a partial degradation of the macromolecular chains, whereas single‐screw extrusion followed by calendering and twin‐screw extrusion provoked an increase of the elastic modulus and of the viscosity. The use of wood flour led to a significant increase of the rigidity, whereas a reduction of the ductility was observed. Because of the very similar aspect ratios of the two different filler size classes, no dramatic differences in the properties were found. These results are useful in order predicting and setting up the optimum preparation and processing strategy for the production of fully biodegradable polymer composites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

甲基化木粉与PE-g-MAH对木粉/HDPE复合材料力学性能的协同作用研究

主要研究了木粉表面甲基化改性和增容剂马来酸酐接枝聚乙烯(PE-g-MAH)对木粉/高密度聚乙烯(HDPE)复合材料力学性能的协同作用.木粉经表面甲基化处理后,与10％PE-g-MAH协同使用,甲基化木粉/PE-g-MAH/HDPE复合材料的拉伸强度、弯曲强度和冲击强度均明显高于未改性木粉/PE-g-MAH/HDPE复合...     

Waste pine cones as a source of reinforcing fillers for thermoplastic composites

In this study, we evaluated some physical and mechanical properties of polypropylene (PP) composites reinforced with pine‐cone flour and wood flour. Five types of wood–plastic composites (WPCs) were prepared from mixtures of cone flour, wood flour, PP, and a coupling agent. The water resistance and flexural properties of the composites were negatively affected by an increase in cone‐flour content. Extractives in the cone flour had a significant effect on the flexural properties of the WPCs. However, the flexural properties and water resistance of the WPC samples were not significantly affected by the addition of 10 wt % of the cone flour when compared to the WPC samples made from wood flour. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effects of vinyltrimethoxy silane on thermal properties and dynamic mechanical properties of polypropylene–wood flour composites

The viability of vinyltrimethoxy silane was investigated as a coupling agent for the manufacture of wood–plastic composites (WPC). The effect of silane pretreatment of the wood flour on the thermal and the dynamic mechanical properties and thermal degradation properties of the composites were studied. Moreover, the effect of organosilane on the properties of composites was compared with the effect of maleated polypropylene (MAPP). DSC studies indicated that the wood flour acts as a PP-nucleating agent, increasing the PP crystallization rate. In general, pretreatment with small amounts of silane improved this behavior in all the WPCs studied. Thermal degradation studies of the WPCs indicated that the presence of wood flour delayed degradation of the PP. Silane pretreatment of the wood flour augmented this effect, though without significantly affecting cellulose degradation. Studies of dynamic mechanical properties revealed that the wood flour (at up to 30 wt %) increased storage modulus values with respect to those of pure PP; in WPCs with a higher wood flour amount, there was no additional increase in storage modulus. Pretreatment of the wood flour with silane basically had no effect on the dynamic mechanical properties of the WPC. These results show that with small amounts of vinyltrimethoxy silane similar properties to the MAPP are reached. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Influence of ammonium polyphosphate modified with 3‐(methylacryloxyl) propyltrimethoxy silane on mechanical and thermal properties of wood flour–polypropylene composites

In this article, the influence of ammonium polyphosphate (APP) and ammonium polyphosphate modified with 3‐(Methylacryloxyl) propyltrimethoxy silane (M‐APP) on mechanical properties, flame retardancy, and thermal degradation of wood flour–polypropylene composites (WF/PP composites) have been investigated. Polypropylene grafted with m‐isopropenyl‐α,α‐dimethylbenzyl‐isocyanate (m‐TMI‐g‐PP) was used to improve the adhesion of WF/PP composites. APP and M‐APP were used as flame retardants. The experimental results demonstrated that addition of M‐APP obviously enhanced mechanical properties of WF/PP composites. According to cone calorimetry results, M‐APP is also an effective flame retardant for WF/PP composites, compared to that of APP. It was also found that M‐APP decreased the 1% weight loss temperature and increased char residue. The thermal degradation of wood flour based upon the first peak temperature of wood decreased from 329.3 to 322.9°C and the thermal degradation of PP based upon the second peak temperature of PP improve from 518.0 to 519.6°C, when M‐APP was added to the WF/PP composites. From SEM results the char layer of the 25% M‐APP systems is much more intumescent than that of the 25% APP systems, indicating that 3‐(Methylacryloxyl) propyltrimethoxy silane can improve the char‐forming ability of WF/PP composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

The effects of maleated polybutadiene‐grafted polypropylene (MAPB‐g‐PP) content on the properties of wood flour/polypropylene composites

This research investigated the effects of a compatibilizer of maleated polybutadiene‐grafted polypropylene (MAPB‐g‐PP) on the properties of wood‐flour/polypropylene composites through the analysis of mechanical properties, water absorption, thermogravimetry, differential scanning calorimetry, and scanning electronic microscopy. The results demonstrate that the mechanical properties of composites were significantly increased; the thermal stability and water absorption were improved. The crystallization temperature and crystallinity were decreased. These improvements have been attributed to the strong interfacial interaction of MAPB‐g‐PP with both wood and polypropylene. J. VINYL ADDIT. TECHNOL., 26:17–23, 2020. © 2019 Society of Plastics Engineers     

Effects of copper amine treatment on mechanical properties of PVC/wood‐flour composites

Copper amine–treated wood flour was added to PVC [poly(vinyl chloride)] matrix in order to manufacture PVC/wood‐flour composites. Effects of copper treatments on the mechanical properties of PVC‐wood composites were evaluated. Unnotched impact strength, flexural strength, and flexural toughness of the composites were significantly improved by the wood‐flour copper treatment. The optimum copper concentration range was 0.2 to 0.6 wt% of wood flour. Fractured surfaces were examined by using scanning electron microscopy (SEM) combined with energy‐dispersive spectroscopy (EDS). PVC/wood interfacial debonding was the main fracture mode of untreated wood‐flour composites, whereas wood‐particle pullout and breakage dominating the fractured surfaces of copper‐treated wood‐flour composites. On the fractured surfaces, more PVC could be found on the exposed copper‐treated wood particles than on untreated wood, a result suggesting improved PVC‐wood interfacial adhesion after copper treatments. J. Vinyl Addit. Technol. 10:70–78, 2004. © 2004 Society of Plastics Engineers.     

Characterization of UHMWPE/wood composites produced via dry‐blending and compression molding

In this study, composites made from wood flour and ultra‐high molecular weight polyethylene (UHMWPE) were produced and characterized. In particular, the composites were initially prepared using a simple dry mixing technique and then compression molded. The effect of wood content on the mechanical properties was determined up to 30wt%. Characterization included scanning electron microscopy to investigate wood dispersion and interfacial bonding quality, while the mechanical tests included tensile, torsion, and flexion. The results show that good dispersion and adhesion was achieved and wood flour addition increased substantially (up to 97%) all the moduli in the range of conditions tested. Finally, it was found that hardness increased by about 5 Shore D points by adding 30% wood flour in UHMWPE. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers     

Thermal and mechanical characterization of linear low‐density polyethylene/wood flour composites

A linear low‐density polyethylene (LLDPE) matrix was modified with an organic peroxide and by a reaction with maleic anhydride (MAn) and was simultaneously compounded with untreated wood flour in a twin‐screw extruder. The thermal and mechanical properties of the modified LLDPE and the resulting composites were evaluated. The degree of crystallinity was reduced in the modified LLDPE, but it increased with the addition of wood flour for the formation of the composites. Significant improvements in the tensile strength, ductility, and creep resistance were obtained for the MAn‐modified composites. This enhancement in the mechanical behavior could be attributed to an improvement in the compatibility between the filler and the matrix. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2775–2784, 2003