羟基锡酸锌阻燃聚氯乙烯电缆材料及其潜在火灾危险性评价

采用氧指数、成炭率、烟密度、垂直燃烧(UL 94)、热重分析、环境扫描电镜和锥形量热的方法测试了羟基锡酸锌(ZHS)对PVC的阻燃抑烟作用。ZHS用量为15%时即可以满足对PVC电缆材料燃烧烟密度的要求,燃烧等级可以达到UL94 V0级。PVC/ZHS电缆材料的热稳定性能、成炭性能和燃烧性能表明,ZHS在PVC电缆材料燃烧时,可以促进PVC交联成炭,生成的炭具有较好的隔氧、隔热及抑制可燃性气体逸出的作用,提高了PVC电缆材料的热稳定性能,有效降低了PVC电缆材料的潜在火灾危险性。     

PVC塑料型材老化试验与思考

本文针对PVC塑料型材老化现象,从引起PVC塑料型材老化的基本观点、人工老化试验、不同地区气候老化影响、老化导致变色的影响因素等方面进行了讨论,提出了解决PVC塑料型材老化现象意见.     

Pilot study on the contamination of drinking water by organotin compounds from PVC materials

Raw and treated water samples and tap water samples from four to six houses located on distribution lines where PVC pipe/tubing had been recently installed were collected in five Canadian municipalities for the analysis of organotin compounds. After derivatisation with sodium tetraethylborate the ethylated organotin compounds were extracted with hexane and analysed by gas chromatography-microwave induced plasma atomic emission spectrometry using a wavelength (326.234 nm) specific for tin. Organotin compounds, mainly methyltin and dimethyltin at concentrations ranging respectively from 0.5 to 257 ng Sn/L and from 0.5 to 6.5 ng Sn/L, were detected in samples from ten of the twenty-two houses. No organotin compounds were detected in raw water or treated water leaving the treatment plant, indicating that the organotin compounds were leaching into the water from some component of the distribution system.     

PVC塑料浸出液对3种海洋微藻光合作用及生长的影响

海洋微塑料作为一类新型环境污染物已经成为全球性环境问题。运用水样叶绿素荧光仪(Water-PAM)研究了不同浓度软聚氯乙烯(polyvinyl chloride, PVC)和硬PVC浸出液(0、50、100和200 g·L~(-1))胁迫下球等鞭金藻(Isochrysis galbana)、中肋骨条藻(Skeletonema costatum)和小球藻(Chlorella sp.)3种海洋微藻叶绿素荧光特性,包括PSⅡ最大量子产量(F_v/F_m)、PSⅡ实际量子产量(Yield)、光化学淬灭(qP)和PSⅡ最大相对电子传递速率(rETR_(max))的变化,同时检测微藻的生长状况。结果表明,球等鞭金藻(金藻门)和中肋骨条藻(硅藻门)的4项光合作用参数在软PVC浸出液胁迫的96 h内均显著下降,且随软PVC浸出液浓度增加,下降幅度增大,在实验后期(48～96 h)达到最小值,表现为抑制作用。96 h时,球等鞭金藻和中肋骨条藻的细胞密度均在软PVC浸出液200 g·L~(-1)处理组达到最小值,分别占对照组的3.20%和11.90%。硬PVC浸出液胁迫对球等鞭金藻和中肋骨条藻的4项光合作用参数具有显著影响(P<0.05),球等鞭金藻的4项参数均显著高于对照组。中肋骨条藻的相关光合作用参数均显著低于对照组。72 h时球等鞭金藻和中肋骨条藻的细胞密度分别在硬PVC浸出液100 g·L-1和200 g·L~(-1)处理组达到最小值,为对照组的67.90%和82.50%,表现为抑制作用。小球藻(绿藻门)的各光合作用参数和细胞密度在软PVC和硬PVC浸出液胁迫的96 h内未产生显著变化。该研究证实PVC浸出液对微藻光合系统具有干扰作用,对海洋生态系统具有潜在风险。     

Determination of Microorganisms’ Attack on Some Flexible Polymers by Using Soil Burial Test Method

Many controversial issues have recently been associated with plasticized poly(vinyl chloride) (pPVC) used in building applications, mainly for flooring. One of them has to do with the health impact of some plasticizers and thermal stabilizers based on heavy metal compounds. Recent advances in the synthesis of polyolefins based on metallocene catalysts can yield similar flexibility for formulations as is now available for those based on pPVC. Polyolefin copolymers are considered to be possible replacements for pPVC. The soil burial test has demonstrated that highly filled polyolefin elastomer formulations having a significant percentage of post-consumer polyolefins (up to 60% in laboratory conditions) have interesting properties from the biodegradation point of view. They are more resistant to microorganisms’ attack than plasticized flooring formulations based on PVC that are currently used, even in a very harsh environment as soil, where complex mixtures of microorganisms are present. The effect of microorganisms’ attack after soil burial was evaluated by visual examination, weight loss, water absorption and changes in mechanical properties.     

Controlling substance flows: The case of chlorine

The contribution of chlorinated hydrocarbons (CHCs) to environmental problems in the Netherlands is discussed in an economic context. The economic interactions within the chlorine market, including the link to caustic soda production, are described, and PVC is taken as a case study. Key policy options are evaluated in terms of their potential for environmental improvement. It appears that 95% of CHC emissions causing environmental problems are due to dissipative applications. With respect to the specific problems of ozone depletion and global warming, only a small group of compounds is responsible for most of the impact. Moreover, economic interactions within the group of CHCs can strongly influence the net effect of environmental policy measures. Policies aimed at a reducing volume output of certain specific groups of CHCs will inevitably lead to trade-offs between environmental problems. The environmental impact of a hypothetical ban on CHCs is discussed in relation to the use of PVC as a sink for chlorine. Both these options appear to have drawbacks. Moreover, no absolute conclusion can be drawn until the environmental impact of CHC substitutes is known.     

电絮凝法处理PVC化工废水的试验研究

利用电絮凝法处理PVC化工废水,研究了极板材料、原水pH值、反应时间、电流密度、极板间距对处理效果的影响。实验结果表明,电絮凝法去除PVC化工废水中的浊度和COD时,在使用铝合金极板,pH值为8.0,电流密度为30 mA/cm2,极板间距为1.5 cm,反应20 min后出水浊度≤5NUT,COD≤60 mg/L。优于传统药剂絮凝对浊度和COD的去除率。电絮凝处理PVC化工废水的机理包括电絮凝、电化学氧化还原及电气浮等协同作用。     

聚氯乙烯(PVC)类医疗废物的热解特性研究

为研究含聚氯乙烯医疗废物的热解特性,选取输液管和尿样盒为对象,利用差热热重分析仪,在氮气气氛下进行热重实验,探讨了二者热失重行为和机制,分析了反应过程中热量变化及热解剩余物性状,建立了反应动力学模型.结果表明,输液管和尿样盒的降解过程以主要成分PVC的热解机制为主导,分别在约200～390℃和约390～550℃区间内,呈现两段主要的热解过程,最大热解速率分别出现在315℃和470℃左右;增塑剂可降低样品脱氯的温度并增加失重率,样品复杂的成分导致失重峰不规则且不平滑;热解过程为吸热反应,呈现2个明显的阶段,分别对应试样的两段热解,热延迟的存在导致DTA峰温稍滞后于对应的DTG峰温;建立的"整体两步四反应模型"能很好地描述输液管和尿样盒的热解行为.     

老化前后轮胎磨损微粒与聚氯乙烯微粒对抗生素的吸附-解吸行为

近年来,微塑料(microplastics,MPs)作为一类新型污染物,广泛存在于水环境中而备受关注.与典型微塑料(PVC、PP、PE和PS)相比,轮胎磨损微粒(tire wear particles,TWP)在组成成分、添加剂种类和理化特性上存在显著差异.为深入比较TWP与典型MPs对有机污染物吸附-解吸行为的不同....     

微压供热堆压力容器结构设计与力学分析

目的对微压供热堆HAPPY200的压力容器进行结构设计及分析。方法针对HAPPY200的特点,满足堆工、热工等专业要求,完成此微压供热堆堆本体的结构设计,并根据ASME锅炉和压力容器规范(ASME BPVC规范)进行压力容器的力学计算校核。微压供热堆HAPPY200采用池壳结合的方式,反应堆200 MW热功率两回路设计,设计压力1.6 MPa,出口温度120℃。压力容器采用不锈钢材质、35 mm壁厚的设计,采用ASMEBPVC规范对其进行力学计算校核。结果此结构中所得到的力学结果均小于ASMEBPVC标准所要求的限值。结论微压供热堆HAPPY200的压力容器设计满足堆工、热工等专业要求,其力学评定通过ASME BPVC规范要求。