Study of poly(vinyl chloride)/acrylonitrile-styrene-acrylate blends for compatibility, toughness, thermal stability and UV irradiation resistance

Physicochemical change and microparticle release from disposable gloves in the aqueous environment impacted by accelerated weathering

The explosive growth of disposable gloves usage in cities around the world has posed a considerable risk to municipal solid management and disposal during the COVID-19 pandemic. The lack of the environmental awareness leads to glove waste being discarded randomly and ending up in the soil and/or the ocean ecosystem. To explore the physicochemical changes and environmental behaviors of disposable glove wastes in the aqueous environment, three kinds of glove (latex, nitrile and vinyl) were investigated. The results showed that the physicochemical characteristics of disposable gloves made of different materials were altered to different degrees by UV weathering. Nitrile gloves were more stable than latex and vinyl gloves after being exposed to weathering conditions. Although the chemical structures were not clearly demonstrated through FTIR after weathering, the SEM results showed significant microscopic changes on the surfaces of the gloves. Analysis of the leachate results showed that UV weathered gloves released leachable substances, including microparticles, organic matter, and heavy metals. Latex gloves were more likely to release microparticles and other substances into the water after UV weathering. The release of microparticles from gloves can also be impacted by sand abrasion. The appropriate strategy needs to be developed to mitigate the environmental impact caused by the discarded gloves.

Effect of temperature on the impact behavior of PVC/ASA binary blends with various ASA terpolymer contents

Acrylonitrile-styrene-acrylic (ASA) terpolymer has a typical core-shell structure with poly(butyl acrylate) (PBA) as the soft core and styrene-acrylonitrile (SAN) copolymer as the hard shell. The impact behavior of poly(vinyl chloride) (PVC)/ASA binary blends with various ASA terpolymer contents was systematically investigated at three different temperatures (23°C, 0°C, and –30°C). With the addition of 30 phr ASA terpolymer, the impact strength of the blends increased by almost 45 times at 23°C and 29 times at 0°C compared with the neat PVC, respectively. Herein, ASA terpolymer particles were related to each other to form a percolation group and the stress field around the ASA particles was connected with each other, thereby more effectively served as the stress concentrators, exhibiting the highest toughening efficiency. In addition, the significantly improved toughness could also be attributed to the special core-shell structure of ASA terpolymer, as well as, a good miscibility between the PVC matrix and the SAN shell of the ASA terpolymer. However, the decreasing temperature limited the flexibility of the PBA chain, resulting in the insignificant role of ASA terpolymer in toughening PVC at –30°C. Moreover, the improvement in the toughness of the blends did not sacrifice its heat distortion temperature.

Composition analysis and characterization of waste polyvinyl chloride (PVC) recovered from data cables

Cables and wires are the indispensable parts of electronic equipments for transmission of both information and electricity. Nowadays, data cables are widely used in the computer equipments for sending information and they become waste once its life cycle is completed. However, recycling of cables and wires are mainly concentrating into the recovery of metals such as aluminium and copper, rather than other polymer present. Polymeric materials from the waste data cables are often disposed into landfills or incinerated, since they have only lower value in recycling yard. From the data cables collected, it has been estimated that the major constituents are copper (58.3%), polyvinyl chloride (19.9%) and polyethylene (16%). Similarly, polycarbonate (2.9%), silicon rubber (1.6%), steel (1.4%) and other material (0.4%) such as cotton cord were also present as minor components. Out of these, polyvinyl chloride is the dominant polymer present in data cables. Hence, the present work investigates the reprocessability of the polyvinyl chloride recovered from the data cables and deals with issues such as premature degradation during life cycle, assessment of plasticizers and degradation after reprocessing. Torque measurement studies using torque rheometer revealed further mechanical recycling possibilites of the recovered polyvinyl chloride. Besides, the applicability of melt blending technique for processing recovered polyvinyl chloride can be found out by analysing thermal behaviour by using thermogravimetric analysis, differential scanning calorimetry and heat distortion temperature.

Room temperature and low temperature toughness improvement in PBA-g-SAN/α-MSAN by melt blending with TPU

Toughness of PBA-g-SAN/α-MSAN blends at room temperature and low temperature was successfully improved by incorporating TPU elastomer.