Plastics: physical-and-mechanical properties and biodegradable potential

Introduction. Processing agricultural waste into plant biodegradable plastics is a promising way for its recycling. This work featured the main physical-and-mechanical properties of plant plastics without adhesive substances obtained from millet husk and wheat husk and wood plastic obtained from sawdust, as well as their biodegradation potential. Study objects and methods. Objects of the study were plastics without adhesives based on wood sawdust, millet husk, and wheat husk. Results and discussion. We analyzed of the physical-and-mechanical parameters of the plant plastic based on millet husk, wheat husk, as well as wood plastic based on sawdust. The analysis showed that, in general, the sbeiigth characteristics of the wood plastics were higher than those of the plastics based on millet husk, especially flexural strength. Thus, the average value of the density of the wood plastic exceeded that of the plant plastic from millet husk by 10%, hardness by 40%, compression elasticity modulus by 50%, and flexural modulus by 3.9 times. It was found that wood and plant plastics obtained from sawdust, millet husk, and wheat husk without adhesives had a high biodegradation potential. Conclusion. The plastics obtained can be used as an insulating, building, and decorative material in the steppe regions experiencing a shortage of wood and wood powder

Synthesis of Cardanol-Containing Resols for Producing Phenolic Films: Protective Coatings for Wood Composites

Abstract: This paper investigates synthesis of impregnating phenol–formaldehyde resins in which up to 30 wt % formulation phenol is replaced by cardanol, a plant product. The resulting resins were used to make impregnated paper for laminating the plywood and particle boards. The synthesis and structure of cardanol-containing water-soluble resols were studied by IR spectroscopy and 1H NMR, and the reactivity of phenol cardanol formaldehyde resins at 80–150°C was studied by differential scanning calorimetry. The optimal amount of cardanol in relation to phenol in the resin structure was determined. It is shown that the introduction of cardanol into the composition of phenol–formaldehyde resins reduces the impregnation time of kraft paper and improves the surface quality and elasticity of the impregnated paper, with the use of such paper making it possible to decrease the water absorption of laminated particle board materials and the emission of formaldehyde. © 2021, Pleiades Publishing, Ltd

Mathematical modeling of bioactivation process for wood raw materials

By the method of mathematical planning of the experiment, the influence of bioactivating the raw material of wood particles with a silt mixture of activated sludge, as well as humidity, lignin content in the press composition and the pressing temperature was investigated. Linear regression equations are obtained which allow predicting the effect of the above factors on the properties of wood plastics without using resin. Optimal values of bioactivation, conditions and factors for obtaining wood plastics without resins with high performance properties by hot pressing were determined. © 2018 CEUR-WS. All rights reserved

Biostability of binder-free wood and plant plastics protected with antiseptics

Introduction. Agriculture produces a lot of plant and food waste that is highly biodegradable. In order to recycle this waste and use it in the production of new materials, we need to find effective ways to increase their resistance to biodegradation. We aimed to study the biostability of binder-free wood and plant plastics, as well as to find an optimal method of their antiseptic protection. Study objects and methods. Our objects of study were binder-free plastics based on sawdust, wheat and millet husks. To determine their biostability, we exposed them in active soil for 21 days and analyzed their physical and mechanical properties. Also, we examined the effects of several methods of antiseptic treatment on the samples' strength, water resistance, and biodegradation. Results and discussion. All the wood- and plant-based samples showed low biostability. Exposure in active soil caused significant morphological and structural changes, as well as impaired the samples' physical and mechanical properties, especially those of the plant-based plastics. Their resistance to biodegradation was significantly determined by the type of filler or antiseptic, as well as by the method of antiseptic administration. Whether added to the press mixture or applied to the surface, the antiseptics changed the samples' physical and mechanical properties. Among the antiseptics used, copper sulfate showed the best effect when introduced directly into the sawdust press mixture. It ensured the lowest decrease in flexural strength, but increased hardness, water absorption, and swelling. The wheat- and millet-based plastics protected with copper sulfate showed an increase in strength indicators, but lower water resistance. Conclusion. The antiseptic protection of binder-free wood and plant plastics affects a number of their physical and mechanical properties and therefore should take into account the expected conditions for their performance. © 2022 Buryndin et al. All Rights Reserved

An Investigation of Complexes of Lignin Found in Plant Raw Materials as a Natural Binder in Obtaining Plastic in Closed Molds

Abstract: It has been suggested that lignin of wood and plant origin is directly involved in the formation of plastics without the addition of binders due to the formation of a net structure. The performed studies using DSC showed the presence of two peaks under the influence of temperature and water—hydrolytic destruction of the lignin–carbohydrate complex and further polycondensation of its “fragments” into a cross-linked polymer with the formation of plastic. The use of catalysts such as polyoxometalates (by the example of manganese-containing sodium vanadomolybdophosphate) makes it possible to carry out preliminary partial destruction of lignin and obtain plastics under “softer” conditions. In this case, it is necessary to take into account the different chemical structure and lignin content in the initial molding material, which determines not only the conditions for obtaining, but also the properties of the resulting material. © 2023, Pleiades Publishing, Ltd