紫外光降解水中痕量NDMA的效能研究

采用紫外光降解水中痕量亚硝基二甲胺（NDMA）,研究了NDMA初始浓度、溶液pH值、光照面积、紫外光辐射强度以及水质对紫外光降解NDMA的影响。络果表明,紫外光能够有效降解水中的NDMA,紫外光解反应5min,NDMA去除率可以达到97．5％。初始浓度对NDMA的光降解去除率影响不大。     

苯并三唑类紫外光吸收剂

比利时的ICI Europa公司开发出一种商品名称为Topanex 100BT的苯并三唑类紫外光吸收剂,添加在PVC制品中可吸收波长范围为2900～3800A的紫外光,而使PVC塑料不致降解、变色和破坏。加入少     

水中微量甲苯的光催化降解研究

紫外光(UV)及紫外光-过氧化氢(H2 O2)对水中微量甲苯均有较好的降解作用,UV-H2 O2 降解效果更佳。研究了UV-H2O2降解中,H2O2用量对降解速率的影响。初步探讨了两种光降解技术的机理。     

第7届全国PVC塑料与树脂技术年会暨“志海”杯优秀论文交流会会议纪要

由全国聚氯乙烯信息站、《聚氯乙烯》编辑部承办的第7届全国PVC塑料与树脂技术年会暨“志海”杯优秀论文交流会于2008年10月15—18日在福建省武夷山市国贸大酒店召开,共有36个单位的56名代表出席了会议。出席此次会议的代表有:全国聚氯乙烯信息站站长、《聚氯乙烯》副主编李少言,锦西化工研究院信息中心副主任高旭东,深圳市志海实业有限公司总经理严一丰,大连实德集团总工薛一心,河北宝硕管材有限公司总工高长全,中国管道商务网首席架构师刘义忠等,会议在热烈融洽的气氛中顺利进行。本次会议以“PVC加工技术与经验交流”为主题,演讲嘉宾介绍了实验成果,分享了工作经验,探讨了生产中的疑难问题,演讲的题目包括:PVC-U硬制品混料工艺及混料效果分析、Ca/Zn稳定剂在PVC制品中的老化性能研究、PVC树脂与无铅增塑PVC紫外光稳定研究、医用PVC粒料颜色发黄原因分析及PVC服务中实际问题分析、悬浮法PVC的熔体黏度与扭矩对塑料加工性和制品力学性能的影响、不同冲击改性剂对PVC/木粉复合材料性能影响的研究、三元共聚物P(MAA-BA-MMA)对PVC/木粉复合材料的性能影响、半补强炭黑对增塑PVC的紫外光稳定和降解的影响、抗冲改性...     

水中己烯雌酚的紫外光降解

研究了内分泌干扰物己烯雌酚（DES）在波长为254nm的紫外光照射下的光分解.研究表明,紫外光直接光解可以有效去除水中DES,其光降解效率受水的pH值和辐射光源的影响.在pH3～10范围内,初始浓度为373μmol/L的DES光降解效率随pH值提高而增大;pH10时,紫外光照射40min,DES的降解率可达98.7%.DES的光降解反应在浓度18.6～186μmol/L范围内符合准一级动力学规律,其光降解反应半衰期为20.6min.GC-MS联机分析表明DES紫外光降解的主要中间产物包括羟基化DES、DES半邻醌和对羟基苯基乙基酮等,这些中间产物可以进一步发生光解而被去除.     

影响PVC树脂聚合物降解的主要因素及预防措施

PVC树脂聚合物出现降解后,会使PVC塑窗异型材制品内在质量降低,外观产生质量问题。本文通过聚合物降解产生的危害、降解机理等的论述,指出了影响PVC树脂聚合物降解物主要因素及预防措施。     

浅析影响PVC树脂聚合物降解的主要因素及预防措施

PVC树脂聚合物出现降解后,会使PVC塑窗异型材制品内在质量降低,外观产生质量问题。本文通过聚合物降解产生的危害、降解机理等的论述,指出了影响PVC树脂聚合物降解物主要因素及预防措施。     

TiO2对聚氯乙烯紫外光稳定与催化降解的影响

综述了普通和纳米TiO_2对聚氯乙烯(PVC)的紫外光稳定和催化降解的机理及研究进展,以及包覆和掺杂改性对TiO_2光稳定和光催化性能的作用。金红石型纳米TiO_2具有优异的紫外光稳定特性,锐钛型纳米TiO_2表现出极强的光催化活性。无机包覆过的金红石型TiO_2对PVC有明显的保护作用。有机改性则能提高锐钛型TiO_2的分散性,从而提高其对聚合物的光催化效率。过渡金属离子掺杂可在TiO_2晶格中引入缺陷位置或改变结晶度,从而改变PVC的光降解速率。     

聚氯乙烯紫外光稳定性研究进展

阐述了聚氯乙烯的紫外光降解和稳定机理,以及聚氯乙烯光降解研究中最新的表征手段。重点介绍了受阻胺类紫外光稳定剂和稀土化合物在聚氯乙烯紫外光降解中的作用和最新应用进展,也介绍了几种紫外光稳定性能好的有机紫外光吸收剂的研究和应用情况。     

紫外光照射下双亲性纳米ZnO固相光催化降解PVC

本文研究了在较弱的紫外光强度下聚氯乙烯(PVC)的固相光催化降解方法。以纳米ZnO为基础,制备了双亲性ZnO,分别以它们为光催化剂,制备了光催化剂-PVC复合膜。研究了复合膜在空气、水相两种不同氛围中的光催化降解情况,通过比较复合膜的失重率,得出有利于塑料降解的条件。实验结果表明,双亲性ZnO-PVC复合膜的光催化降解效果好于ZnO-PVC复合膜;与在空气氛围中进行相比,光降解过程在水相中进行速率更快。     

Enhancement of Photostabilization of Poly(vinyl chloride) Doped with Sulfadiazine Tin Complexes

New sulfadiazine tin complexes were synthesized in 67–80% yields from the reaction of sulfadiazine, and different organotin(IV) chlorides and their structures were established. The synthesized complexes were used as additives at a low concentration (0.5% by weight) to enhance poly(vinyl chloride) (PVC) photostability. The PVC samples containing sulfadiazine tin complexes (thickness = 40 μm) were fabricated and irradiated with ultraviolet light at room temperature for 300 h. The changes that occurred within the PVC samples upon irradiation were investigated by inspecting the loss in weight, reduction in the average molecular weight, formation of small degradation fragments containing polyene, carbonyl, and hydroxyl moieties, and changes in the ultraviolet absorption intensity of polymeric materials. The surface morphology of irradiated PVC samples was investigated using optical, atomic force, and scanning electron microscopies. There were lesser changes within the PVC samples with sulfadiazine tin complexes compared to the blank PVC sample. The dimethyltin(IV) complex was found to be the most efficient additive in stabilizing PVC against irradiation. The role played by the complexes in reducing the photodegradation of PVC was investigated, and a mechanism was proposed. J. VINYL ADDIT. TECHNOL., 26:370–379, 2020. © 2019 Society of Plastics Engineers     

Effect of sands on poly(vinyl chloride) resistance to ultraviolet light

Summary Laminates made of poly(vinyl chloride) (PVC) and sands were irradiated by ultraviolet light (UV) under normal atmospheric conditions. Three different types of sand (mine, beach and river) were utilized at various concentrations levels. The effect of the sands upon flexural mechanical properties of the laminates with varying irradiation times was analyzed. It is shown that degradation induces a decrese in mechanical properties of PVC laminates but this may be prevented by adding mine sand at specific volume concentration.     

Improvement of photostability and thermal stability of PVC by carbon quantum dots loaded on TiO2

Titanium dioxide (TiO₂) has a strong oxidation effect when absorbing ultraviolet light. Therefore, when TiO₂ is used as a light stabilizer in polyvinyl chloride (PVC), it will cause the photodegradation of PVC. Herein, carbon quantum dots (CQDs) coated TiO₂ composite (TiO₂@CQDs) was prepared by a one-step hydrothermal method. The prepared TiO₂@CQDs were characterized by transmission electron microscopy (TEM), UV–Vis spectroscopy, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The photostability of PVC film containing TiO₂@CQDs was investigated via photodegradation conductivity test, weight loss rate test, and ultraviolet aging test. Due to the down-conversion effect of CQDs under ultraviolet light, its existence can alleviate the photoaging of PVC. In addition, the thermal stability of PVC containing TiO₂@CQDs was studied by conductivity tests and oven thermal aging tests. The presence of CQDs significantly improved the thermal stability of PVC. Meanwhile, the HCl absorption capacity of CQDs could reach 30.8 mg/g_cat. According to the DFT calculations, this high absorption capacity is attributed to the HCl immobilization effect via forming hydrogen bonds between HCl and the keto oxygen, carboxyl keto oxygen in CQDs. The hydroxyl group in CQDs could also combine ZnCl₂ by forming a coordination bond.     

Ultraviolet light aging properties of PVC/CaCO3 composites

The ultraviolet radiation aging behaviors of PVC/CaCO₃ and PVC/CaCO₃/macromolecular modifier composites were studied through whiteness measurement, Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, scanning electron microscopy, and mechanical properties test. It was found that nano‐CaCO₃ particles used as ultraviolet light screening agents could significantly enhance the antiaging properties of PVC materials. Due to the macromolecular modifier coated on nano‐CaCO₃ particles, the compatibility of nano‐CaCO₃ and PVC matrix was improved, resulting in uniform dispersion of nano‐CaCO₃ in PVC matrix. Therefore, the PVC/CaCO₃/MP composite exhibited better antiaging properties than PVC/CaCO₃ composite. After 12 h of ultraviolet irradiation, the tensile strength retention, elongation at break retention, and impact strength retention of PVC/CaCO₃/MP composite were 79.5%, 74.5%, and 75.3%, which were much higher than that of neat PVC and PVC/CaCO₃ composite. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

PVC/ABS共混材料老化及其防老化研究

分析了PVC/ABS共混材料的老化及其防老化机理,并通过在PVC/ABS基础配方中添加紫外线吸收剂、抗氧剂等办法,研究不同品种的紫外线吸收剂和抗氧剂对提高PVC/ABS共混材料防老化能力的影响,结果表明,紫外线吸收剂UV 327和抗氧剂1076能有效提高PVC/ABS共混材料的防老化能力。     

ABS/PVC共混复合材料耐老化性能研究

在ABS／PVC基础配方中通过添加紫外线吸收剂、抗氧剂等助剂，研制了耐老化ABS／PVC共混塑料，并研究了不同品种的紫外线吸收剂和抗氧剂对提高ABS／PVC共混复合材料耐老化性能的影响。结果表明，紫外线吸收剂UV-327和抗氧剂1076能有效提高ABS／PVC共混塑料的耐老化性能。     

Photoaging and stabilization of rigid PVC/wood‐fiber composites

Ultraviolet (UV) weathering performance of unpigmented and rutile titanium dioxide pigmented rigid polyvinyl chloride (PVC)/wood‐fiber composites has been studied. The composite samples were manufactured by dry‐blending PVC, wood fibers, and other processing additives in a high‐intensity mixer. The dry‐blended compounds were extruded and compression molded into panel samples. The manufactured samples were artificially weathered using laboratory accelerated UV tests. Composite samples were exposed to 340‐nm fluorescent UV lamps and assessed every 200 h, for a total of 1200 h of accelerated weathering. Each assessment consisted of a visual examination of surface roughness or erosion, a contact angle measurement, a FTIR collection, and a color measurement. The experimental results indicated that wood fibers are effective sensitizers and that their incorporation into a rigid PVC matrix has a deleterious effect on the ability of the matrix to resist degradation caused ultraviolet irradiation. The light stability of these composites could be improved quite efficiently with the addition of rutile titanium dioxide photoactive pigment during formulation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1943–1950, 2001     

聚丙烯酸酯/TiO2复合粒子对PVC性能的影响

采用扫描电子显微镜,差示扫描热仪和高压毛细管流变仪,研究了聚丙烯酸酯/TiO_2复合粒子改性PVC的形貌、玻璃化温度和流变性能；结合力学性能测试,研究了复合粒子改性PVC的耐紫外光性能。结果表明：随着复合粒子用量的增加,PVC的玻璃化温度呈下降趋势；加入质量分数为3%的复合粒子,能改善PVC的流动性能,且使PVC呈现韧性断裂特征；与没有添加复合粒子的PVC相比,复合粒子改性PVC经紫外光辐照后的力学性能保持率较高,复合粒子能有效提高PVC的耐紫外光能力。     

The mechanism for inorganic fillers accelerating and inhibiting the UV irradiation aging behaviors of rigid poly(vinyl chloride)

The UV irradiation aging behaviors of PVC composites with several inorganic fillers were studied through Fourier transform spectroscopy (FTIR), ultraviolet spectroscopy (UV‐Vis), differential scanning calorimeter (DSC), scanning electron microscopy (SEM), and mechanical property test. It was found that incorporation of a small amount of the inorganic fillers such as CaCO₃, talc and SiO₂ could hold up the UV aging behaviors of PVC. Those filler‐filled PVC composites sheets after 20 days UV irradiation maintain lower carbonyl index (CI) and good appearance of surfaces, as compared with the corresponding neat PVC sheets, ascribed to high reflection of those fillers to UV light. While montmorillonite (MMT) and pyrophyllite fillers could accelerate the UV aging behaviors of PVC, which could be concluded from both the sharp increase of the CI and lower T_g due to the chain scission reactions because of their high absorbance of these fillers to UV light in 290–400 nm. In these two PVC composites, UV irradiation caused the deterioration of their mechanical properties and the appearance of rough, cracked and chalked surfaces after 20 days UV irradiation. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011