木塑复合材料的生物因子危害研究进展

综述了生物因子对木塑复合材料(WPC)的侵蚀情况,主要介绍了霉菌、腐朽真菌、白蚁、藻类、细菌及海生生物等对WPC的危害情况,并对提高WPC生物因子抗性的方法进行了初略探讨。     

上海衡复历史文化风貌区白蚁危害与区域白蚁治理

对上海衡山路-复兴路历史文化风貌保护区的白蚁危害进行了分析,提出了房屋白蚁与庭院树木白蚁必须进行同步治理。采用以地下型白蚁监测-控制系统为主的综合治理措施进行区域白蚁治理,可逐步降低特定区域内的白蚁种群密度,达到有效降低整个区域内白蚁发生率、危害率。     

木塑复合材料真菌耐久性研究进展

综述了木塑复合材料(WPC)的真菌耐久性的研究情况,主要介绍了WPC的真菌危害情况(包括腐朽真菌降解及霉菌侵染等)和影响其真菌耐久性的主要因素,并对提高WPC真菌耐久性的方法进行了探讨,为WPC真菌耐久性的提高及其相关标准的制定奠定基础。     

化学合成防白蚁剂和具杀蚁活性的生物源物质及其衍生物

白蚁是世界上五大害虫之一.目前,全世界已记载白蚁种类有3 000种左右,其中185种白蚁被认为是害虫.白蚁蛀食含纤维类的物质,并能够消化纤维素,对植物和建筑物危害严重.白蚁分布遍布世界,喜在热带、亚热带生活,其危害面积约占世界陆地总面积的50％.在中国,已记载白蚁种类有476种,主要危害房屋建筑、水库堤坝、农林作物和电缆交通设施等.中国每年因白蚁危害造成的经济损失约20亿～25亿人民币. 研究还发现,全球数量巨大的白蚁会产生甲烷,使地球气温升高;由其产生的CO2约占地球上每年CO2释放总量的20％;此外,它们排放的大量蚁酸造成的污染已超过汽车和工业烟雾等对环境的影响.     

湘谭市房屋建筑的白蚁危害及其防治

白蚁是世界性的重要害虫 ,其危害面广 ,涉及到国民经济的许多部门 ,造成了巨大的经济损失。根据我国 2 3个城市的调查统计 ,白蚁造成的损失每年达 10亿元。全国每年因白蚁危害房屋木构件的损失达 15亿元左右。白蚁主要靠蛀食木材和含纤维素物品来生活 ,白蚁还能破坏诸如塑料、橡胶、玻璃纤维、铅铝制品及金属仪器、军用炮弹、沥青等。因此 ,白蚁的危害与人民的衣、食、住、行密切相关。1　白蚁危害的现状湘潭市位于长江以南 ,湖南中部 ,气候温和 ,雨量充沛 ,最适宜白蚁生长、繁殖 ,是湖南省白蚁危害地区之一。通过调查 ,我市发现白蚁有 4科 …     

湖南白蚁危害现状及防治对策

介绍了当前危害湖南省的主要白蚁种类及其危害现状和主要特点 ,分析了湖南省白蚁防治中存在的突出问题 ,提出了相应的防治对策。     

湖南白蚁危害现状及防治对策

介绍了当前危害湖南省的主要白蚁种类及其危害现状和主要特点,分析了湖南省白蚁防治中存在的突出问题,提出了相应的防治对策。     

介绍几种防治白蚁的有效药剂

白蚁是热带、亚热带地区的一种常见的害虫。它繁殖力很强,成熟的白蚁在繁殖期间,24小时内可产卵6000～8000粒。如果一对雌雄蚁在适合的环境条件下,3～5年内即可发展成为几万只甚至百万只白蚁的蚁巢,扩巢蔓延为害。白蚁主要喜欢生活在温暖潮湿的地方,它分布广,活动隐蔽,对人们的建设及生活,造成的危害较大。一、常用防治白蚁的药物①亚砒酸。又叫亚砷酸、砒霜、三氧化     

常用白蚁防治药剂的降解、持效期的研究与探讨

综述了过去和目前常用的白蚁防治药剂如氯丹、灭蚁灵、毒死蜱、联苯菊酯、吡虫啉等的特点、降解性、持效性以及对白蚁的生物活性等方面的研究情况。为合理了解和预测这些药剂对白蚁的持效期提供理论依据。针对目前常用药剂对白蚁的持效期都达不到15年的特点,提出了有必要改进防治方法或修订白蚁防治包治期的建议,例如使用饵剂监控系统、进行重复施药等。     

谈谈白蚁与人类的密切关系

白蚁对人类的危害几乎涉及到国民经济的各个部门，它被列入世界性的五大害虫之一，但是，事物总是一分为二的，而白蚁益又鲜为人知。本文重点论述白蚁益，略述白蚁害。     

Food Exploitation in Termites: Indication for a General Feeding-Stimulating Signal in Labial Gland Secretion of Isoptera

The paired labial glands are located in all termite species in the thorax. During food exploitation workers of the French termite Reticulitermes santonensis and the African termite Schedorhinotermes lamanianus release the secretion of their labial glands directly onto the food. The secretion carries a water-soluble, heat-resistant, nonvolatile signal that stimulates gnawing and feeding and leads to aggregations of feeding workers. In a feeding bioassay, extracts of the labial glands of 11 termite species from five families all proved to have this feeding-stimulating effect both on R. santonensis and S. lamanianus. The heat resistance of the feeding-stimulating signal also could be shown for selected species from all termite families tested. A combined thin layer chromatography–feeding bioassay on cellulose TLC plates showed that after chromatography of labial gland secretion, the feeding-stimulating signal is located in all 11 species in the same area from R_f 0.46 to 0.88. An extract of labial glands of cockroaches stimulated feeding in R. santonensis and S. lamanianus as well, but was not active after heat treatment and after TLC. This points towards a general feeding-stimulating signal having evolved only in the labial gland secretion of termites.     

Properties of flat‐pressed wood plastic composites containing fire retardants

This study investigated physical, mechanical, and fire properties of the flat‐pressed wood plastic composites (WPCs) incorporated with various fire retardants (FRs) [5 or 15% by weight (wt)] at 50 wt % of the wood flour (WF). The WPC panels were made from dry‐blended WF, polypropylene (PP) with maleic anhydride‐grafted PP (2 wt %), and FR powder formulations using a conventional flat‐pressing process under laboratory conditions. The water resistance and strength values of the WPC panels were negatively affected by increasing the FR content as compared to the WPC panels without FR. The WPC panels incorporated with zinc borate (ZB) gave an overall best performance in both water resistance and strength values followed by the panels containing magnesium hydroxide (MH) and ammonium polyphosphate (APP). For these three FR's, the best fire resistance as measured in the cone calorimeter was obtained with the 15 wt % APP treatment and then followed by 15 wt % ZB, or 15 wt % MH formulations. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Flexural properties of surface reinforced wood/plastic deck board

Decking and railing is the largest and fastest growing market for wood–plastic composites (WPCs). Despite WPC's advantages in comparison to lumber, its modulus and creep resistance need to be further improved for demanding structural applications. In this study, WPC deck boards were reinforced by the composite sheets made of commingled glass and polypropylene fiber. Various reinforcement arrangements were carried out to identify the optimal one. Scanning electron microscopy revealed good bonding at the reinforcement/WPC interface. All reinforced samples exhibited considerably increased modulus of rupture, modulus of elasticity, and strain at break. The creep resistance of the reinforced WPC boards was also greatly improved. Creep strain was simulated with Findley's model. Master curves of creep compliance were generated by time–temperature–stress superposition principle. The Prony series was found to be the analytical expression of the master curves with acceptable accuracy. With improved mechanical properties, the reinforced WPC board can be used in more demanding applications. POLYM. ENG. SCI., 47:281–288, 2007. © 2007 Society of Plastics Engineers.     

一种木塑防霉功能母粒的制备及应用研究

木塑复合材料(WPCs)是近年来广泛应用的一种新型复合材料,兼有木材和高分子材料二者的优点,但同时也存在一个很大的弊端:易受霉腐真菌的危害.本文研制了一种木塑防霉功能母粒SD-28M,分析了其活性成分的耐热性、抗霉菌能力和对皮肤的刺激性,对添加此功能母粒的木塑的防霉性能、力学性能和对皮肤的刺激性进行了相关测试和应用研究...     

发光型木塑复合材料的制备及性能研究

针对木塑复合材料材料的低附加值,结合碱土铝酸盐与传统木塑制备了发光型木塑复合材料,既赋予了材料特殊性能的同时,也解决了碱土铝酸盐的耐候性差、易水解的问题。采用正交试验研究分析了材料的力学性能、发光性能,并结合扫描电子显微镜与稳态荧光光谱分析材料间内部结合与发光性能之间的关联。结果表明,发光型木塑复合材料的最佳工艺参数为：聚丙烯（PP）含量为70 %、余料比例为1∶1.5、偶联剂含量为1.5 %、热压时间为10 min;拉伸强度和冲击强度最大能够达到22.2 MPa和12.55 kJ/m²;发光型木塑复合材料的最佳激发区均在380~450 nm之间,完全覆盖发光盐的最佳激发波段400~440 nm,激发波段广,适用范围广;发光盐在复合材料内部可以有效发光,且在加工过程当中没有对碱土铝酸盐产生化学影响。     

热水处理对HDPE/稻壳塑木复合材料尺寸及耐磨性能的影响

对高密度聚乙烯(HDPE)/稻壳粉塑木复合材料进行了两种温度的热水处理,分别浸泡3、6、9、12、15h,测试其尺寸稳定性及表面耐磨性能。结果表明:热水浸泡后,塑木复合材料的尺寸三个方向均会因吸水膨胀,但是膨胀率和膨胀尺寸都较小,其表面磨损质量和磨损深度也没有产生明显增加,热水处理的温度及时间对塑木复合材料的尺寸及表面耐磨性能没有明显影响。同时,证明了刚玉粒度180目的 3号砂布更加适合对塑木复合材料的耐磨性能进行评价。     

Effect of microencapsulated ammonium polyphosphate on flame retardancy and mechanical properties of wood flour/polypropylene composites

Microencapsulated ammonium polyphosphate (MCAPP) was prepared by using melamine–formaldehyde (MF) resin via polymerization in situ. The product was characterized by Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, energy dispersive spectroscopy, water solubility tests, water contact angle, and thermogravimetric analysis. The tests indicate that ammonium phosphate (APP) was successfully coated by the MF resin, and MCAPP with lower water solubility and higher water resistance outperformed APP. After modification by MCAPP, the flammability of wood–plastic composites (WPCs) was investigated by limiting oxygen index (LOI) and cone calorimetry. The results showed that MCAPP/WPC had higher LOI value, lower heat release rate, and more char residual at the end of cone calorimetry than APP/WPC, indicating that the WPC used MCAPP as flame retardant performed better flame retardancy than the WPC mixed with unmodified APP. Moreover, all measured mechanical properties of MCAPP/WPC were distinctly better than APP/WPC. POLYM. COMPOS., 37:666–673, 2016. © 2014 Society of Plastics Engineers     

木粉疏水改性对HDPE基木塑复合材料性能的影响

采用一种操作简便且易于工业推广的方法对木粉进行疏水改性,具体过程为：将3种可热聚合的单体,即甲基丙烯酸甲酯（MMA）、甲基丙烯酸丁酯（BMA）和苯乙烯（St）均匀喷洒在木粉上,经过预热处理后,与配方中其他组分,如高密度聚乙烯（HDPE）和马来酸酐接枝聚乙烯（MAPE）等通过高速混合机混合均匀,采用双螺杆挤出机造粒后,注射制备木塑复合材料（WPC）样条,测试其力学性能。另外,考察了疏水改性对WPC接触角、维卡软化温度、洛氏硬度、吸水性能、热性能的影响规律。结果表明：疏水改性后WPC的接触角增大,木粉和HDPE的界面相容性改善,力学性能得到明显提高。其中,当MMA、BMA和St的添加量为3%时,WPC的力学性能最好,与疏水改性前相比,弯曲强度分别提高了17.3%、26.3%和27.5%,弯曲模量分别提高了24.4%、24.4%和26.0%,冲击强度分别提高了54.7%、57.7%和60.5%。 此外,疏水改性后WPC的维卡软化温度、洛氏硬度、耐水性和耐热性也得到改善。     

Effect of biological degradation by termites on the flexural properties of pinewood residue/recycled high‐density polyethylene composites

Wood–plastic composites (WPCs) are considered to be highly durable materials and immune to any type of biological attack. However, when one of these composites is exposed to accelerated weathering, its surface is affected by the appearance of cracks, which constitute an ideal access route for biotic agents. Although the destruction of wood caused by termites is recognized worldwide, information on their effects on WPC‐based products is scarce. Thus, in this study, we aimed to examine the effects of termite attacks on weathered and nonweathered pinewood residue/recycled high‐density polyethylene composites. In this study, WPCs with 40 wt % wood were prepared. Test samples obtained by compression molding and profile extrusion were subjected to weathering cycles for 1000 and 2000 h with a UV‐type accelerated tester equipped with UVA‐340 fluorescent lamps. Afterward, specimens were exposed to the attack of higher termites (Nasutitermes nigriceps) native to the Yucatan Peninsula. Subsequently, flexural mechanical essays, Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) analyses were performed. FTIR spectroscopy and DSC showed that the surfaces of the compression‐molded specimens were degraded to a higher extent because of the accelerated weathering. The microscopy results revealed that severe damage was caused by the termites on the surface of the compression‐molded samples. Statistical analysis of the mechanical test results showed that biotic attack produced significant changes in the samples previously exposed to accelerated weathering. The results show that the processing method directly affected the sample performance because of differences in the surface composition. The profile‐extruded composites seemed to better resist termite attack. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013