Laser-based techniques: Novel tools for the identification and characterization of aged microplastics with developed biofilm

Microplastics found in the environment are often covered with a biofilm, which makes their analysis difficult. Therefore, the biofilm is usually removed before analysis, which may affect the microplastic particles or lead to their loss during the procedure. In this work, we used laser-based analytical techniques and evaluated their performance in detecting, characterizing, and classifying pristine and aged microplastics with a developed biofilm. Five types of microplastics from different polymers were selected (polyamide, polyethylene, polyethylene terephthalate, polypropylene, and polyvinyl chloride) and aged under controlled conditions in freshwater and wastewater. The development of biofilm and the changes in the properties of the microplastic were evaluated. The pristine and aged microplastics were characterized by standard methods (e.g., optical and scanning electron microscopy, and Raman spectroscopy), and then laser-induced breakdown spectroscopy (LIBS) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) were used. The results show that LIBS could identify different types of plastics regardless of the ageing and major biotic elements of the biofilm layer. LA-ICP-MS showed a high sensitivity to metals, which can be used as markers for various plastics. In addition, LA-ICP-MS can be employed in studies to monitor the adsorption and desorption (leaching) of metals during the ageing of microplastics. The use of these laser-based analytical techniques was found to be beneficial in the study of environmentally relevant microplastics.

Development of Starch-Based Bioplastic from Jackfruit Seed

In this article, jackfruit seed starch plasticized with common plasticizers was developed and characterized. At the first step, the research papers that dealt with the fabrication and characterization of starch-based bioplastics were synthesized and analyzed. Next, jackfruit seeds were selected as a source for starch because of their large availability, low price or even free, and high starch capacity. Afterward, a starch-based bioplastic fabrication procedure was proposed. From preliminary tests, plasticizers were sufficiently selected, including water, glycerol, natri bicarbonate, and acid citric. Using different combinations of these plasticizers, four types of bioplastics were then fabricated to study the effect of the plasticizers as well as to characterize the properties of the corresponding bioplastics. A cutting tool for ASTM D412 type A standard tensile testing specimen was then designed and fabricated. Using these dog-bone specimens, tensile results showed that the hardness of the fabricated bioplastic was positively proportional to the ratio of the starch. Furthermore, from SEM characterization, the bioplastic specimens were fully plasticized. Although the fabricated bioplastic has lower mechanical properties than petroleum-based plastics, its environmental friendliness and high potential added value promise to be a material of the future.

Study of the Rheological Properties of PVC Composites Plasticized with Butoxyethyl Adipates

Polyvinyl chloride compositions are widely used to obtain various types of products. In the composition of the PVC composite, one of the main ingredients is a plasticizer, the introduction of which makes it possible to vary the characteristics of the obtained polymeric materials and products and significantly expand the range of their application. Manufacturability in the processing of polyvinyl chloride compositions serves as an important criterion for the suitability and economic efficiency of the developed plasticizer. In the modern world, the high quality of products is directly related to their environmental safety. In this regard, the work describes the production of environmentally friendly plasticizers based on adipic acid and ethoxylated butanol. Their physicochemical indicators have been investigated. The effect of the obtained additives on the rheology of PVC composites has been studied. The values of the flow characteristics of the melts of the developed PVC compositions plasticized with butyl butoxyethyl adipate and decyl butoxyethyl adipate were estimated. It was shown that the fluidity of melts, in comparison with compounds of a similar composition containing industrial dioctyl phthalate, is characterized by even slightly higher values.