3种薄木贴面木塑复合材料蠕变性能比较

研究采用薄木贴面木塑复合材料代替实木作为办公家具异型封边材料的适用性。通过分析不同树种对薄木贴面PVC基木塑复合材料静曲强度和蠕变性能的影响规律,确定较佳薄木种类。结果表明:在不同树种的薄木贴面中,抗蠕变性能由大到小依次为:黑胡桃>小鞋木豆>栎木。在一定时间(48 h)内,各组试验样品的最终挠度值随载荷增加而增大。黑胡桃薄木贴面在3种试验材料中最适宜作为办公家具异型封边材料使用。     

木塑复合材料热变形温度研究

以现有木塑工厂生产配方为基础,通过改进配方,采用熔融共混方法对木塑复合材料的耐热性进行研究.结果表明:在原有木塑厂生产配方基础上,基体树脂聚乙烯回料用量减少15％,同时添加10％的共聚型聚丙烯新料和5％玻纤,工业化放大生产制得的木塑复合材料热变形温度从61℃提高到99℃;弯曲强度从25 MPa提高到32 MPa;冲击强度从3.5 kJ/m2提高到3.7 kJ/m2,且生产成本并未明显提高.     

The effect of mineral fillers on the thermal properties of wood-plastic composites

Abstract

The thermal properties of wood-plastic composites with five different mineral fillers were studied. The tested mineral fillers were calcite (CaCO₃), two different qualities of wollastonite, soapstone, and talc. The amount of wood, mineral, and plastic (polypropylene) was kept constant. Only the mineral type has been changed during the tests. The thermal behavior of the samples was studied by using a differential scanning calorimeter, a thermogravimetric analyzer and by determining the heat build-up. The analyzed properties were compared with a reference sample made without adding any minerals. The results show that the addition of mineral fillers does not remarkably change the thermal stability of composites. All the studied mineral fillers except soapstone had a small effect on the heat build-up.     

Effects of nanoclay on physical and mechanical properties of wood-plastic composites

Effects of nanoclay (NC) on physical and mechanical properties of wood-plastic composite (WPC) were studied here. Virgin, recycled, and mixed (50/50% of virgin/recycled) polyvinyl chloride (PVC) were used as the matrix in the WPC. Specimens with three NC contents of 1.5%, 3%, and 5% were manufactured; they were then compared with control specimens. Totally, 12 treatments were manufactured. The physical and mechanical properties were measured in accordance with the ASTM standards. The highest properties were found in specimens made from virgin PVC. Addition of recycled PVC resulted in significant decrease in all properties. NC improved all physical and mechanical properties studied in the present research project; the highest properties were observed in specimens with 5% of NC content. The improvement in properties was as a result of formation of bonds between the hydroxyl groups of NC with the wood flour components. It was concluded that NC would significantly improve the properties in all the three PVC types of virgin, recycled, and mixed. From an industrial point of view, it was concluded that mixing virgin and recycled PVC can be recommended not only to decrease production costs, but also to partially solve the problem of PVC residue which are not bio-degradable.     

温湿处理环境对木塑复合材弯曲性能的影响

木塑复合材在使用时应考虑不同的环境条件对材料性能的影响,本文研究了不同密度的聚丙烯基木塑复合材经高/低温和浸水处理后材料的弯曲性能的变化情况,为木塑产品的生产和应用提供依据。     

Preliminary study of the effects of EVA coupling agents on properties of wood-plastic composites

As a hot-melt adhesive, ethylene-vinyl-acetate (EVA) has been used in many industrial applications. But studies of the application of EVA in wood-plastic composites (WPC) are relatively few, so we have investigated the proposition of whether EVA is a suitable coupling agent for WPC or not. The results show that EVA with 8% VA is not a suitable coupling agent, because it reduces the mechanical properties of WPC without any significant effect on its physical properties. With an increase in the amount of wood powder, the mechanical properties of WPC decrease and the ability of water absorption of WPC increases.     

Chemical characterization and biological activity of essential oils from Daucus carota L. subsp. carota growing wild on the Mediterranean coast and on the Atlantic coast

The essential oils and supercritical CO(2) extracts of wild Daucus carota L. subsp. carota growing spontaneously in Sardinia and in Portugal were investigated. The main components in the Sardinian essential oil of flowering and mature umbels with seeds are beta-bisabolene (17.6-51.0%) and 11-alpha-(H)-himachal-4-en-1-beta-ol (9.0-21.6%); instead, the oils from Portuguese samples are predominantly composed of geranyl acetate (5.2-65.0%) and alpha-pinene (3.5-37.9%). Supercritical extracts contain lower amounts of monoterpenes and higher amounts of sesquiterpene hydrocarbons. Antifungal activities of the Sardinian oils were the highest, particularly for dermatophytes and Cryptococcus neoformans, with MIC values of 0.16-0.64 microL mL(-1).