A Simulation Software for the Prediction of Thermal and Mechanical Properties of Wood Plastic Composites

Modelling and simulation has become an important tool in research and development. Simulation models are used to develop better understanding of the internal properties and impact of various parameters on the final quality of the product or process. Simulation model reduces the number of experiments and saves the wastage of material, time and money and are widely used in automobile industry, aircrafts manufacturing, process engineering, training for military, health care sector and many more. Wood Plastic Composite （WPC） is a bio-composite made by mixing wood fibers and plastic granules together at high temperature by compression molding or injection molding. A large quantity of WPC is rejected due to poor quality and low mechanical strength. There is a need to improve the understanding of the wood plastic composites, with both theoretical and experimental analysis. The impact of various parameters and processing conditions on the final product is not known to the industry people, due to less simulation models in this field. A new simulation software WPC Soft is developed to predict the mechanical and thermal properties of WPC. The software can predict the mechanical and thermal properties of WPC. The simulation results were validated with the experimental results and it was observed that the predicted values are quite close to the experimental values and with the further refining of the model, prediction can be further improved. The present simulation software can be easily used by the industry people and it requires very little knowledge of computers or modeling for its operation.

Effects of Rice Hull Particle Size and Content on the Mechanical Properties and Visual Appearance of Wood Plastic Composites Prepared from Poly（vinyl chloride）

This research aims to develop Wood Plastic Composites （WPCs） from rice hull and poly（vinyl chloride） （PVC）. The in- fluences of the rice hull particle size and content on the mechanical properties and the visual appearance of the WPC decking board were investigated. The experimental results revealed that the impact strength tended to decrease with increasing rice hull content. The composites with larger particle sizes exhibited higher impact strength. Under tensile and flexure load, higher rice hull content induced greater modulus and ultimate strength when the rice hull was applied at less than 60 phr. Beyond this concentration, the modulus and the strength dropped due to the formation of rice hull agglomerates. The smaller particles of the milled rice hull, the greater tendency there was for them to act as a pigment to form a darker shade close that of the rice hull on the composite decking board. The larger particle sizes were 106 μm and beyond simply embedded in the white PVC matrix.

Impacts of freezing and thermal treatments on dimensional and mechanical properties of wood flour-HDPE composite

Wood plastic composite （WPC） of wood flour （WF）, high density polyethylene （HDPE）, maleic anhydride-grafted polyethylene （MAPE） and lubricant was prepared by extrusion, and then exposed to different temperatures to evaluate the effects of freezing and thermal treatment on its dimensional and mechanical properties. At elevated temperatures, WPC expanded rapidly initially, and then contracted slowly until reaching an equilibrium state. Treatment at 52°C and relative humidity of 50% for 16 days improved the mechanical properties of WPC： flexure, tensile strength, and izod unnotched impact strength increased by 8%, 10% and 15%, respectively. Wide-angle X-ray diffraction （XRD） tests showed that the degree of crystalization of HDPE in WPC declined with increasing treatment temperature.

Novel wood-plastic composite fabricated via modified steel slag:Preparation,mechanical and flammability properties

A novel method was developed to enhance the utilization rate of steel slag(SS).Through treatment of SS with phosphoric acid and aminopropyl triethoxysilane(KH550),we obtained modified SS(MSS),which was used to prepare MSS/wood-plastic composites(MSS/WPCs)by replacing talcum powder(TP).The composites were fabricated through melting blending and hot pressing.Their mechanical and combustion properties,which comprise heat release,smoke release,and thermal stability,were systematically investigated.MSS can improve the mechanical strength of the composites through grafting reactions between wood powder and thermoplastics.Notably,MSS/WPC#50(16wt%MSS)with an MSS-to-TP mass ratio of 1:1 exhibited optimal comprehensive performance.Compared with those of WPC#0 without MSS,the tensile,flexural,and impact strengths of MSS/WPC#50 were increased by 18.5%,12.8%,and 18.0%,respectively.Moreover,the MSS/WPC#50 sample achieved the highest limited oxygen index of 22.5%,the highest vertical burning rating at the V-1 level,and the lowest horizontal burning rate at 44.2 mm/min.The formation of a dense and stable char layer led to improved thermal stability and a considerable reduction in heat and smoke releases of MSS/WPC#50.However,the partial replacement of TP with MSS slightly compromised the mechanical and flame-retardant properties,possibly due to the weak grafting caused by SS powder agglomeration.These findings suggest the suitability of MSS/WPCs for high-value-added applications as decorative panels indoors or outdoors.

Mechanical Properties and Fire Retardancy of Wood Flour/High-Density Polyethylene Composites Reinforced with Continuous Honeycomb-Like Nano-SiO_(2)Network and Fire Retardant

The mechanical properties of wood flour/high-density polyethylene composites(WPC)were improved by adding a small amount of nano-SiO_(2)to obtain a network-structured WPC with a continuous honeycomb-like nano-SiO_(2)network.The wood flour was modified with a fire retardant(a mixture of sodium octabonate and amidine urea phosphate)to improve its fire retardancy.The flexural properties,creep resistance,thermal expansion,and fire retardancy of the WPC were compared to a control(WPCCTRL)without nano-SiO_(2)or fire retardant.The flexural strength and modulus of the WPC containing only 0.55 wt.%nano-SiO_(2)were 6.6%and 9.1%higher than the control,respectively,while the creep strain and thermal expansion rate at 90°C were 33.8%and 13.6%lower,respectively.The cone calorimetry tests revealed that the nano-SiO_(2)network physically shielded the WPC,giving it lower heat release and smoke production rates.The thermal expansion was further decreased by incorporating fire retardants into the WPC,which showed the lowest total heat release and total smoke production and the highest mass retention.This study demonstrates a facile procedure for producing WPC with desired performances by forming a continuous honeycomb-like network by adding a small amount of nanoparticles.

Effects of calcium carbonate on preparation and mechanical properties of wood/plastic composite

In order to reduce the cost and improve the performance of wood/plastic composite(WPC),the effects of additive amount of calcium carbonate on preparation and mechanical properties of high density polyethylene(HDPE)based WPC were studied.The results showed that the calcium carbonate can improve preparation and mechanical properties effectively.The 20%calcium carbonate additive could effectively improve the melt fluidity of the composites and reduce the energy consumption in the processing.The calcium carbonate had a favorable toughening effect on polymer and was effectively filled in WPC.For the best tensile,flexural and impact properties of WPC,the appropriate additive amounts of calcium carbonate were 25%,10%and 30%,respectively.The additive amount for preparation of WPC should be based on the processing requirements and the demands for different working conditions.

Flame Retardant and Mechanical Properties of Wood Powders/PE Composites

The influence law of ammonium polyphosphate(APP) and coupling agents on the mechanical properties and flame retardant properties of wood powder/PE composites were studied by mechanical test and limited oxygen index(LOI) test. The experimental results show that the LOI of composites increased from 18.7%to 26.5%when the content of APP flame retardant was 30%,however the mechanical properties decreased.The maleic anhydride graft PP,titanate and silane coupling agent were used to improve mechanical properties of composites and it was implied that titanate and silane coupling agent can improve the mechanical properties of composites obviously.The limited oxygen index of wood powder/PE composites reached 27.5% when the content of titanate was 2%. Thermogravimetric analysis(TGA) shows that APP promoted charring and increased the amounts of char,thus protecting the inner matrix and increased the amount of residual char at higher temperature. The titanate coupling agent further increased the charring formed and strengthened the thermal stability,so obviously increased the flame retardant of composites.

Wood Plastic Composites Prepared from Biodegradable Poly（butylene succinate） and Burma Padauk Sawdust （Pterocarpus macrocarpus）： Water Absorption Kinetics and Sunlight Exposure Investigations

Wood plastic biocomposites of biodegradable poly（butylene succinate） （PBS） and Padauk sawdust was successfully pre- pared by using a twin screw extruder and an injection molding machine. The effects of water absorption and sunlight exposure on some properties of the composites were investigated. Water absorption of PBS composites was found to follow the Fick＇s law of diffusion, while the diffusion coefficient increased with increasing wood content. Maximum water absorption of around 4.5% was observed at 30 wt.% sawdust. Optical micrograph indicated the swelling of wood particles by around 1% - 3% after 30 days of water immersion. The tensile and flexural strengths reduced slightly both under the water immersion and sunlight exposure. After 90 days of exposure, the composites clearly looked paler than the non-weathered ones. Thermal scan indicated the re- duction of crystalline region due to the plasticization effect derived from water molecules.

Production of mahogany sawdust reinforced LDPE wood–plastic composites using statistical response surface methodology

We produced wood–plastic composite board by using sawmill wastage of mahogany（Swietenia macrophylla） wood and low density polyethylene.We used multi-response optimization to optimize the process parameters of composite board production including mixing ratio,fire retardant（%） and pressing time（min）.We investigated the effects of these three process parameters in the mechanical and physical properties of the composite board.Afterwards,Box–Behnken design was performed as response surface methodology with desirability functions to attain the optimal level of mixing ratio,fire retardant and pressing time（min）.The maximum modulus of elasticity（MOE） and modulus of rupture（MOR） were achieved at the optimal conditions of wood plastic mixing ratio of60：40,pressing time of 9 min and zero fire retardant percentage.The optimized MOR and MOE were 13.12 and1,781.0 N mm-2,respectively.

The properties of flax fiber reinforced wood flour/high density polyethylene composites

Flax fiber(FF) was used to reinforce wood flour/high density polyethylene composites(WF/PE).WF/PE particles were uniformly mixed with FF via high-speed mixing and then extruded with a single screw extruder to prepare FF reinforced WF/PE composites(FF/WF/PE).Mechanical testing,dynamic mechanical analysis,scanning electron microscopy(SEM),creep measurement and Torque rheology were used to characterize the resulting composites.The results indicate that the mechanical performance of the composites could be remarkably improved by adding a limited amount of FF.The flexural strength and modulus increased by 14.6 and 51.4%,respectively(FF content of 9 wt%),while the unnotched impact strength could be increased by 26.5%(FF content of12 wt%).The creep resistance and toughness of thecomposite was markedly improved without changing the plastic content of the composite material.

Evaluation of Sawdust and Rice Husks as Fillers for Phenolic Resin Based Wood-Polymer Composites

We produced Wood-Polymer Composites (WPCs) with phenolic resin (PR) filled with saw dust (SD) and rice husks (RH) in a PR:fillerratio of 60:40 wt.%. RH and SD were grinded and sieved into particles μm. The aim of this research work was to evaluate sawdust and rice husks as fillers for sustainable phenolic resin based WPCs. Therefore, we investigated the thermal stability of PR/RH and PR/SD WPCs then we studied and compared the tensile, flexural properties of PR/SD and PR/RH WPCs samples, as well as their dimensional stability after water absorption test. Furthermore, through ultraviolet light exposure, we evaluated the effects of photo-oxidation on the water stability and mechanical properties of PR/RH and PR/SD WPCs samples compared to unexposed ones. PR filled with SD presented better mechanical properties compared to PR/RH WPCs samples. However, PR/RH WPCs showed good mechanical properties, and better thermal resistance and better water repulsion capabilities compared to PR/SD WPCs samples. Although, long time UV exposure ended up lowering considerably the mechanical properties and water resistance of PR/SD and PR/RH WPCs, both RH and SD offer great added value as fillers for PR based WPCs;SD having better interactions with PR matrix compared to RH.

烟秆粉和咖啡壳粉对木塑复合材料性能的影响

为探讨烟秆粉和咖啡壳粉代替桉木粉生产木塑复合材料的可行性,采用范式法分析比较烟秆粉、咖啡壳粉和桉木粉的化学成分,以烟秆粉、咖啡壳粉及桉木粉为增强相与高密度聚乙烯(HDPE)熔融共混,采用两步挤出成型法制备了不同木质纤维原料及配比的木塑复合材料。通过测试不同木塑复合材料的物理力学性能、动态热力学性能(DMA)、氧化诱导时间(OIT)和氧化诱导温度(OIT^(*)),观察不同木塑复合材料的微观形貌和官能团,分析不同木质纤维原料及配比对木塑复合材料性能的影响。结果表明:综纤维素含量由高到低依次为桉木粉、烟秆粉、咖啡壳粉,木质素含量由低到高依次为桉木粉、烟秆粉、咖啡壳粉;桉木粉/HDPE复合材料(TS0)的综合性能优于烟秆粉/HDPE复合材料(TS100)和咖啡壳粉/HDPE复合材料(CS100)。在混合纤维原料木塑复合材料中,随着桉木粉用量的减少,木塑复合材料的集中载荷、弹性模量、静曲强度和冲击强度先增加后降低,OIT和OIT^(*)降低,20%烟秆粉80%桉木粉/HDPE复合材料(TS20)的综合性能最佳,其集中载荷和冲击强度比TS100分别提高27.5%和22.5%,OIT和OIT^(*)分别增加9.9 min和10.7℃。

矿物钢塑复合材料与木塑复合材料性能对比研究

对矿物钢塑复合材料板材与传统木塑复合材料进行系统表征,并对外观及微观结构、无机组成成分、热性能和力学性能等进行了对比分析研究。扫描电镜(SEM)结果表明,矿物钢塑复合材料板材的形状规则、无翘曲变形,样品断面较为密实,而木塑板材液氮脆断面存在界面剥离,易发生变形翘曲。红外光谱(FTIR)结果表明,三种板材的基体材料均为聚氯乙烯(PVC)树脂,其特征峰与PVC红外光谱类似。热重分析(TG和DTG)表明,木塑复合材料的热失重速率和质量损失率大于其余两种矿物钢塑,矿物钢塑的热稳定性较木塑复合材料得到了较大提升。随着铸造灰和钢渣的加入,复合材料的弯曲强度和模量均得到了提高,且经铸造灰填充的矿物钢塑力学性能为三者中最高,其弯曲强度和弯曲模量分别为33.0 MPa和4.72 GPa。矿物钢塑复合材料具有优异的热性能、力学性能,作为一种新型绿色环保材料,为我国大宗工业固废的高附加值回收提供一种新的解决方案。

高填充油茶果壳基木塑复合材料的制备及力学性能

以油茶果壳和不同塑料即聚丙烯、高密度聚乙烯(PE-HD)、低密度聚乙烯、线性低密度聚乙烯为原料,采用模压成型的方法制备了高填充油茶果壳基木塑复合材料,利用电子万能试验机和悬臂梁冲击试验机测试其力学性能。通过单因素试验分析塑料种类对复合材料力学性能的影响,确定较优塑料种类后进一步优化制备参数。以壳粉含量、增容剂马来酸酐接枝聚乙烯(MAPE)含量、热压温度、热压时间为设计因素,以弯曲强度、弯曲弹性模量、拉伸强度、冲击强度为力学性能优化目标,设计L_(9)(3^(4))正交试验,研究了高填充油茶果壳基木塑复合材料的制备工艺,利用极差分析和方差分析得到了较优配方和工艺参数组合。研究表明:当添加塑料为PE-HD时,复合材料的弯曲强度最大为34.40 MPa,拉伸强度最大为18.20 MPa,力学性能较优;壳粉含量为65%时,添加7%MAPE的复合材料强度较好,弯曲强度最大为33.66 MPa;优化制备参数组合为壳粉含量55%,MAPE含量5%,热压温度160℃,热压时间10 min。

PLA/PPC/CS复合材料的制备工艺

通过在聚乳酸(PLA)/玉米秸秆(CS)复合材料中引入聚碳酸亚丙酯(PPC)改善韧性,使用熔融挤出与热压成型相结合的方式制备聚乳酸/聚碳酸亚丙酯/玉米秸秆(PLA/PPC/CS)复合材料,以热压时间、热压压力和热压温度为变量,以PLA/PPC/CS复合材料的冲击、弯曲和拉伸性能为评价指标设计单因素试验.试验结果表明,热压时间、热压压力、热压温度对PLA/PPC/CS复合材料的力学性能影响显著.最终优化出的热压工艺条件为热压时间10 min,热压压力7.5 MPa,热压温度190℃.

一种麦秸纤维替代木粉制备的景观用复材特性研究

为提高园林景观建筑材料的环保性、强度和耐水性等,试验以麦秸纤维代替传统木粉,并加入剑麻纤维,制备了一种木塑复合材料(WPC),并对其性能进行研究。试验结果表明,麦秸纤维可以代替木粉制备WPC,制备出的WPC力学性能相差不大;剑麻纤维的掺入,可以提升WPC的力学性能和耐水性;当掺20 phr麦秸纤维、5 phr长度5 mm的剑麻纤维时,试验制备的WPC材料弯曲、拉伸强度分别达到53.6、16.8 MPa,弯曲弹性模量为4200 MPa,吸水率低于7%,材料具备较好的强度性能,韧性和耐水性良好。试验制备的木塑复合材料综合性能良好,可以作为园林景观建筑材料实际应用。

芦苇纤维用量对芦苇纤维/聚乙烯(PE)复合材料力学性能的影响

以芦苇纤维作为增强体,以高密度聚乙烯(HDPE)和线性低密度聚乙烯(LLDPE)共混物作为基体,制备芦苇纤维/聚乙烯(PE)复合材料。探讨了芦苇纤维用量对复合材料力学性能以及微观结构的影响。结果表明:当LLDPE和HDPE的质量比为30∶70、芦苇纤维用量为30%时,所得复合材料的综合性能较好;静曲强度达到最高值25.9 MPa,较PE共混材料提升了12.1%;拉伸强度达到最高值22.3 MPa,较PE共混材料提升了14.4%;冲击强度为6.7 KJ·m^(-2)。

DOPO衍生物/八氨丙基POSS阻燃木塑复合材料的研究

先合成OA-POSS与DPA,然后将其引入到WF/PP木塑复合材料中,通过热压成型方法制备阻燃WF/PP木塑复合材料,进行热失重分析及阻燃性能、力学性能测试,探究了阻燃木塑复合材料的热稳定性能、燃烧性能和力学性能。结果表明:DOPO、DPA和OA-POSS的加入一定程度上提高了复合材料的初始热分解温度,降低了热分解速率,明显提高材料的热解残余物质量。DOPO,DPA和OA-POSS的加入能够显著提高复合材料的阻燃性能,复合材料的残炭量明显增加,最高增加228.05%。DOPO的加入使材料力学性能下降,而DPA和OA-POSS的加入一定程度上增强了复合材料的力学性能。

木塑复合材料紫外耐老化性能研究进展

木塑复合材料因其外形美观、力学性能优异、对环境友好,被广泛运用于建筑模板、公共设施等领域,但现阶段服役于室外环境中的木塑复合材料存在颜色稳定性差、耐老化性能较弱等问题。本文基于国内外相关学者对木塑复合材料紫外老化性能进行的大量理论分析与试验研究,系统地总结了材料老化后微观形貌、表观颜色、力学性能3个方面的研究进展;并对改善木塑复合材料紫外耐老化性能的措施进行了阐述,其中添加耐老化助剂这一方法经济成本低且效果较好,被广泛研究应用。通过系统综述,总结了现阶段木塑复合材料紫外耐老化性能研究中存在的问题,并对未来发展趋势进行展望,以期促进木塑复合材料的研究与工程应用,满足更多领域日益发展的特殊功能需求。