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.

Starch-Based Adhesives for Wood/Wood Composite Bonding: Review

Increasing global energy crisis and scarcity of petroleum resources has shifted focus of chemical industries to look for alternative raw material resources. The main focus of raw materials in wood adhesives, such as petroleum and natural gas [1] [2], would be gradually replaced by renewable biopolymers. Starch is a relatively inexpensive and renewable product from abundant plants, easy processing and it has been extensively used as binders, sizing materials, glues and pastes [3], but its bonding capacity is not strong enough to glue wood [4]. Extensive research has been carried out on improving the cohesive properties, especially water resistance, of starch-based adhesives. In starch-based wood adhesive many new approaches have come forward for effective use it in wood/wood composite adhesive giving comparable performance as synthetic adhesives. This review of starch-based adhesives is made with the focus on starch modification methods for improving properties of starch-based adhesives.

Morphological, Rheological and Mechanical Properties of Pla-Typha Based Biocomposites

Due to the demand from society for the consumption of ecological polymeric materials, one of the polymers that have satisfied this request is the poly (lactic acid) (PLA). This polymer is derived from renewable resources, it is recyclable and biodegradable. It presents a good understanding between the promising properties and the cost. However, a route to increase the mechanical properties and reduce the cost of PLA is the elaboration of PLA based biocomposites by using fillers from natural waste. In this work, The effect of Typha content on the morphological, rheological, thermal and mechanical properties of PLA matrix was studied. Four formulations were produced with different mass concentrations. The results showed an increase in the viscoelastic properties, as a function of the Typha stem powder concentration. The DSC analysis showed an increase in the crystallinity rate of the various composites confirming the nucleating effect provided by the filler. TGA analysis indicated a decrease in the decomposition temperature of the composites. Mechanical tensile tests have shown a significant improvement in the mechanical properties mainly for the samples containing 45% (w/w) of Typha powder.

石木塑复合地板标准解读

简述了《石木塑复合地板》(LY/T 3303—2022)制定过程,对该标准的主要技术内容进行解读。在大量调研、试验的基础上,确定了石木塑复合地板的外观质量、规格尺寸及其偏差、理化性能等指标。为标准的正确理解和使用提供参考,也将为规范石木塑复合地板市场提供有效的理论依据和技术支撑。

石木塑地板及其相关产品标准比较研究

针对石木塑地板及其相关产品标准进行比较,分析石木塑地板及其相关产品标准在质量要求等方面的差异,为中国石木塑地板的生产、贸易和标准制修订提供参考。

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.

Additive manufacturing of mechanical testing samples based on virgin poly （lactic acid） （PLA） and PLA/wood fibre composites

3D printing in additive manufacturing is con-sidered as one of key technologies to the future high-pre-cision manufacturing in order to benefit diverse industriesin building construction, product development, biomedicalinnovation, etc. The increasing applications of 3D printedcomponents depend primarily on their significant merits ofreduced weight, minimum used materials, high precisionand shorter production time. Furthermore, it is very crucialthat such 3D printed components can maintain the same oreven better material performance and product quality asthose achieved by conventional manufacturing methods.This study successfully fabricated 3D printed mechanicaltesting samples of PLA and PLA/wood fibre composites.3D printing parameters including infill density, layer heightand the number of shells were investigated via design ofexperiments （DOE）, among which the number of shells wasdetermined as the most significant factor for maximisingtensile strengths of PLA samples. Further, DoE workevaluated the effect of material type （i.e., neat PLA andPLA/wood fibres） and the number of shells on tensile,flexural and impact strengths of material samples. It issuggested that material type is the only predominant factorfor maximising all mechanical strengths, which howeverare consistently lower for PLA/wood fibre compositeswhen compared with those of neat PLA. Increasing thenumber of shells, on the other hand, has been found toimprove almost all strength levels and decrease infillcavities.

木塑复合材料的界面改性方法

表面有机化改性是提高木质填料(木纤维或木粉)的分散程度和增强其与聚合物基体界面相互作用的重要手段。对于木塑复合材料而言,木质填料与树脂基体的界面粘接程度是有效传递载荷、提高力学性能、降低吸水率和提高尺寸稳定性的关键因素。针对国内外木塑复合材料的研发现状,本文主要概述了木质填料的表面处理方法及其对木塑复合材料性能的影响。

木粉组分对木塑复合材料性能的影响研究进展

木塑复合材料通常由木粉和热塑性树脂复合而成。木粉自身由纤维素、半纤维素、木质素以及抽提物等多种成分组成,各组分对复合材料的各项性能产生不同的影响。本文对该领域的相关研究进展进行了概述,主要包括:纤维素能提高木塑复合材料的力学性能、吸水性和导电性,不利于耐候性及热稳定性;半纤维素对复合材料性能存在负面影响;木质素能降低复合材料的吸水性,提高热稳定性和生物耐候性,不利于耐光老化性;脱除抽提物能够提高复合材料的吸水性、力学性能、热稳定性和耐光老化性,不利于耐腐性。今后的研究可致力于将木粉中的组分进行分离或部分脱除,深入研究木粉各组分对复合材料的影响及其机理,为制备更高性能的木塑复合材料提供理论基础。

塑木复合材与木材主要力学性质的比较研究

分析了塑木复合材与木材的抗弯强度、抗弯弹性模量、抗压强度和抗剪强度之间的差异 ,结果表明 ,塑木复合材的抗弯性能远低于鹅掌楸 (Liriodendronsp.)和速生杨木 (Populussp .) ;纵向抗压强度也低于木材的顺纹抗压强度 ,横向抗压强度为木材横纹抗压强度的 2 .95倍 (I- 6 9杨 )～ 3.74倍 (鹅掌楸 ) ,纵向抗剪强度与木材的顺纹抗剪强度与木材相当。因此可采用降低密度、改进材料结构或改进材料成型方式来增加塑木复合材料的抗弯性能和纵向抗压性能 ,以扩大其应用范围。

微发泡木塑复合材料的研究进展

针对PE/木纤维、PVC/木纤维、PP/木纤维、PS/木纤维四种微发泡木塑复合材料体系,介绍了国内外在性能改进及工艺设备方面取得的一些进展。分析了目前该领域的现状及今后的发展方向,并展望了微发泡木塑复合材料未来的应用领域及市场前景。

苯乙烯(St)/甲基丙烯酸甲酯(MMA)/丙烯腈(AN)三元接枝共聚塑合木研制

本文报道了采用苯乙烯／甲基丙烯酸甲酯／丙烯腈（ＳＭＡ）三元共聚单体浸入木材细胞壁与激活的纤维素进行接枝聚合反应，构成新型的高分子复合材料（ＳＭＡ－ＷＰＣ），经物理机械性能、吸水性、耐酸性检测，该材料硬度比素木提高了２０％～３５％，抗压强度提高了３５％～４５％，经９８％浓硫酸３天浸泡，重量损失率下降２２％，而在水介质８天浸渍，吸水率下降５０％，并通过扫描电镜观察了塑化前后的微观结构。

偶联剂对木塑复合材料性能的影响

研究了两种偶联剂——马来酸酐(偶联剂1)和异氰酸酯(偶联剂2)对木塑复合材料性能的影响。确定木材纤维与热塑性聚合物的比例7:3、复合材料的设计密度为0．7g／cm3,在热压温度175℃、热压时间8min、偶联剂1或偶联剂2 加入比例均为2％的试验条件下,对比分析偶联剂产生的作用。结果表明:偶联剂2对复合材料的力学性能影响显著;对于同一种偶联剂,所用的热塑性聚合物材料不同,对复合材料性能的影响也存在较大的差异。

聚合物改性水玻璃均相杂化液对速生杨木的改性

将丙烯酰胺单体在钠水玻璃溶液中聚合制成水玻璃-聚丙烯酰胺均相杂化液,通过浸渍法使杂化液与速生杨木材复合,制成无机/有机木材复合材。SEM、FT-IR表征了速生杨木与杂化前驱液复合前后的结构和形貌变化,研究了复合木材的热稳定性及力学性能的变化,结果表明,用该均相杂化液改性的复合木材WPG为31.6%时,其氧指数为50.3%;并且与素材的力学性能相比,复合木材的抗弯曲强度较素材提高了11.2%,弹性模量提高了18.2%,其径面、弦面和端面的硬度分别提高了15.6%、17.3%和26.2%。

西南桤木木塑复合材料的研究

采用乙烯基类系列单体———丙烯腈 (AN)、甲基丙烯酸甲酯 (MMA)、丙烯酸 (AA)三元共聚单体注入西南桤木木材中 ,制成新型的高分子复合材料 (AMA WPC)。单体的注入用满细胞法 ,聚合用热引发法 ,并采用添加氯化锌对木材细胞壁进行活化等工艺对木塑复合材进行了研究和分析。实验样品按照国标GB192 7-194 3有关规定进行测试 ,并结合傅立叶红外光谱和扫描电镜探讨了各因素对AMA WPC材料接枝率及性能的影响。结果表明 :改性后西南桤木木塑复合材料具有优异的物理、力学性能。与素材相比较 ,AMA WPC的密度提高了 5 9 8% ,顺纹抗压强度提高了 76 7% ,抗弯强度提高了 90 4 % ,抗弯弹性模量提高 2 2 2 % ,端面硬度提高 10 2 3% ,径面硬度提高 15 3 6 % ,弦面硬度提高 15 2 2 % ,吸水率降低 5 6 7% ,湿膨胀率降低 19 0 %。

聚氯乙烯/稻壳粉木塑发泡制品的研究

通过模压成型方法对聚氯乙烯/稻壳粉木塑发泡制品进行了研究,分析了稻壳粉的不同填充量、不同处理方法、不同增塑剂用量以及工艺条件对复合材料性能的影响。由研究结果可知:稻壳粉含量为40份时,制品的综合性能较好;稻壳粉以硅烷偶联剂处理效果较好;随DOP的用量加大,制品的拉伸强度降低,冲击性能和发泡性能提高;实验中,工艺条件的控制是一个极为重要的因素,它直接影响制品的性能。

增容剂对再生聚丙烯/木粉复合材料性能的影响

以再生聚丙烯(PP)、锯末木粉为原料,采用双螺杆挤出机挤出造粒制备了塑木复合材料。研究了增容剂马来酸酐接枝PP(PP-g-MAH)用量对再生PP/木粉复合材料吸水性、拉伸性能、弯曲性能、冲击性能、硬度和热变形温度等性能的影响,并采用扫描电子显微镜分析了材料的断面形态。结果表明,PP-g-MAH可以增加木粉与PP的界面结合力,提高复合材料的性能,其最佳用量为6～9份。

辐射法制备木塑复合材地板

报道了以四川桦木地板坯为基材、浸渍MMA、St/UPE为主体的多元混合浸渍液 ,采用6 0Coγ射线辐射聚合制备WPC地板的方法。研究了木材孔隙率、木材密度、浸渍条件对木材浸渍率的影响。研究了MMA、St/UPE、吸收剂量、聚合物留存率对WPC地板性能的影响。制备出了耐磨性提高 3倍、冲击压痕提高 3.7倍、硬度提高 1.8倍、吸水率降低 78.6 %、湿胀率降低 6 5.6 %、抗胀率为 6 5.

木塑复合材料的应用及其发展前景

介绍了木塑复合材料的成分、加工工艺,该材料的适用范围及其力学性能,以及国内外木塑复合材料制品的发展现状和市场前景,为加快我国木塑复合材料产业的发展,提出了三点意见。

稀土偶联剂在再生PP／木粉复合材料中的应用研究

用稀土偶联剂(WOT)处理木粉,对改性木粉进行了红外光谱分析;将改性木粉、再生聚丙烯(PP)及其它助剂用双螺杆造粒机组挤出造粒制备PP/木粉复合材料,研究了WOT用量、木粉用量对复合材料性能的影响,并采用扫描电子显微镜进行了材料断面的形态分析。结果表明,WOT与木粉之间的化学结合作用可以增强木粉与PP的界面结合,提高了塑木复合材料的性能,合适的WOT用量为4～6份(每100份木粉)。木粉用量在20～60份时,复合材料的拉伸弹性模量、弯曲弹性模量和热变形温度随木粉用量的增加而提高。