【正文】 氧化鎂采用的是MAGOX公司的產(chǎn)品。金紅石鈦白粉為Sayman Chemical Materials生產(chǎn)的Kronos 2220 型TiO2。膨脹體系和膨脹性能可以用折射指數(shù)、膨脹度、平均粒度來表示。這些產(chǎn)品擁有令人滿意的密度、泡沫結(jié)構(gòu)、色澤和表面性能。已經(jīng)有一些廠商用50%?的回收再利用的聚氯乙烯材料制成的電纜用于新車的制造。泡沫聚氯乙烯材料可以用作管材的內(nèi)層材料，在這樣的情況下，要求的密度并不那么高。通過加入新的瓶子薄片材料來進(jìn)行穩(wěn)定，那么會非常有效的阻止降解，即使新材料的含量很低（比如30%）、經(jīng)過了15次循環(huán)利用，都非常有效。關(guān)于再回收利用聚氯乙烯瓶裝材料機械性能的調(diào)查表明，使用后的廢液在強度和延展度上有很大的降低。以這些制品的變色情況和一些力學(xué)性能為依據(jù)，最終從中選出能夠良好外觀的最適合的聚氯乙烯組分。聚氯乙烯也會因為受到紫外線輻射而降解。2 材料和方法戶外用聚氯乙烯門窗異型材產(chǎn)品，每百分質(zhì)量的聚氯乙烯樹脂中通常主要添加有5分的穩(wěn)定劑，5分金紅石型鈦白粉，5分填料。因此，用這樣的組合來減少太白粉的使用而不增加制品使用壽命退化和減少的的速度是非常好的做法。一個重要的缺點是鈦白粉的成本，與碳酸鹽和滑石粉等填料或顏料相比，其價格往往要高得多。他們的研究，通過顏色的變化、拉伸強度和斷裂伸長率、粘度的降低和脆裂時間，對降解和穩(wěn)定反應(yīng)進(jìn)行了檢測。這種通常被稱為協(xié)同作用的行為，讓他們想到了使用馬來酸丁基錫和三硝基及其酯類同系物的共混物。穆罕默德等人發(fā)現(xiàn)，巴比妥酸和硫代巴比妥酸是兩種高熔點、無毒的有機熱穩(wěn)定性的材料。脫氯化氫反應(yīng)很有可能是一種連鎖反應(yīng)機制，反應(yīng)過程中會產(chǎn)生自由基中間體。氧氣有助于紫外線產(chǎn)生自由基并傳播氧化作用，因此，氧氣造成的光降解是長效的。聚合反應(yīng)過程中產(chǎn)生活性基團是不可避免的。但是，這種方式很少發(fā)生，因為大多數(shù)的聚合物不能夠不經(jīng)過發(fā)生降解反應(yīng)過程就消耗掉激發(fā)能量。一旦該反應(yīng)開始，PVC就會迅速并逐步發(fā)生外觀（如表面質(zhì)量、光澤、粉化、顏色、電性能、拉伸強度和延伸率）上的變化，并最終達(dá)到完全脆化和降解。在降解的過程中PVC的物理性質(zhì)會發(fā)生脆化。另外有一些能夠抗紫外線的純聚合物則由于會吸收紫外線形成污染源而已經(jīng)被淘汰。而一些人造高能量輻射源如汞弧燈、氙弧燈、碳弧燈以及各種日曬燈能發(fā)出波長低于290納米的輻射波，這些輻射波對塑料的降解作用比自然陽光更強。而市面上的各種聚氯乙烯中還有一些可以用于擠出具有剛性且不含增塑劑成分的產(chǎn)品。外文資料翻譯 A study on usability of magnesium oxide with titanium dioxide in PVC door and window profiles1. IntroductionPolyvinyl chloride is among the most widely used synthetic organic polymer materials. Plasticized polyvinyl chloride positions are widely encountered as, for instance,vinyl sheet goods and as objects formed from chloride is mercially available in a variety of grades, some of which are suitable for preparing rigid,plasticizerfree positions for extrusion .For plastics, prolonged exposure to the sun’s electromagnetic radiation in the ultraviolet (UV) region can lead to photooxdiation and degradation of physical properties, often manifested by color change and embrittlement. Similarly,the UV ponent of ordinary fluorescent lighting can degrade polymers and many of the additives used with them.The effective UV radiation that does reach the earth’s surface extends from about 290–400 nm. This range happens to include the highest energy ponent UV band, and the segment around 300 nm, which is the most distractive to plastics. Some manmade highenergy radiation sources mercury arc lamps, xenon arcs, carbon arcs, and various sunlamps can emit radiation at wave lengths below 290 nm and these can degrade plastics even more severely than natural sun light. Hence, they are often used for accelerated testing of plastics.The energy content of UV radiation in the 290–400 nm can rupture most of the chemical bonds present in polymer structures. Not all the polymers are equally affected by UV radiation, and some have a degree of resistance, otably polymethyl methacrylates and fluorocarbons. Others, that in their pure forms could be expected to be resistant to UV, are degraded because of contaminants present that act as sites for UV energy absorption.Absorption of radiation energy by polymer produces molecular excitations: if the level of absorbed energy is high enough, it can activate a chemical reaction whereby internal bonds (carbon to carbon, carbon to hydrogen, carbon to halogen, etc.) are broken so that polymer degradation results. PVC is damaged by dehydrochlorination (release of hydrogen chloride), autooxidation and echanochemical chain scission. This degradation is caused by the simultaneous sequence of these reactions.Dehydrochlorination, prevailing reaction during processing,leads to increasing discoloration. In the course of the proceeding degradation the physical properties are also changed in the direction of increasing embrittlement. PVC of ideal constitution should be thermally stable, which was concluded from investigations with model substances. Therefore, it has to be assumed that the damage, articularly the dehydrochlorinations, starts from sites of the macromolecule with labile chlorine–carbon bonds. PVC can be degraded by heat and sun lights. The release of hydrogen chloride, which is the indication of PVC degradation in prolonged exposure to the sun’s electromagnetic radiation in the UV region, is occurred according to the following reactions:The color of PVCbased article is changed from yellow to bla