Biodegradable materials — Present situation and future perspectives

Abstract

Biodegradable polymers constitute a loosely defined family of polymers that are designed to degrade through the action of living organisms. They offer a possible alternative to traditional nonbiodegradable polymers if recycling is impractical or not economical. The main driving force behind this technology is the solid waste problem, particularly with regard to the decreasing availability of landfills, the litter problem and the pollution of marine environment by non‐biodegradable plastics. Technologies like composting used for the disposal of food and yard waste are the most suitable for the disposal of biodegradable materials. European Standardisation Committee (CEN), Organic Reclamation and Composting Association (ORCA) and German Institute for Standardisation (DIN) have already defined, at a draft level, the basic requirements for a product to be declared compostable. They are based on: complete biodegradability of the product in a time period compatible with composting, measured through respirometric tests (ASTM D5338‐9, ISO/CD14855, etc); disintegration of the material during the fermentation phase; no negative effects on compost quality; checking of laboratory‐scale results on pilot/full‐scale composting plants. These requirements set forth a common base for a universal marking system to readily identify products to be composted. Thermoplastic starch‐based polymers and aliphatic polyesters are the two classes of biodegradable materials with the greatest near‐term potential. This paper reviews a great variety of properties, structures and biodegradation behaviour of thermoplastic starch in combination with poly(vinyl alcohol) or some aliphatic polyesters like poly(hydroxybutyrate‐co‐hydroxyvalerate), poly(lactic acid), poly(ϵ‐caprolactone) and poly(butanediyl succinate).

Poly(Lactic Acid) Packaging Modified Curcumin as Bioactive Substance in Tea Drink (Camelia sinensis)

“…To improve the function of PLA packaging in maintaining the quality of tea drink, was adding bioactive substances such as curcumin which had antioxidant and antimicrobial activity. Antioxidant was defined as a compound which can delay, making slower and prevent the oxidation process, whereas antimicrobial is a compound which can kill or inhibit the growth of microorganism [2].…”

Polymer in Agriculture: a Review

“…In agricultural field, polymers are also widely used for many applications [1] . Although they were used, in the first time, just as structural materials for creating a climate beneficial to plant growth (inhert polymers), in the last decades functionalized polymers revolutionized the agricultural and food industry with new tools for the molecular treatment of diseases, rapid disease detection, enhancing the ability of plants to absorb nutrients etc.. Smart polymeric materials and smart delivery systems helped the agricultural industry combat viruses and other crop pathogens, functionalized polymers were used to increase the efficiency of pesticides and herbicides, allowing lower doses to be used and to protect the environment indirectly through filters or catalysts to reduce pollution and clean-up existing pollutants [2][3][4] . This report will review the key aspects of used polymers in agricultural area, highlighting current research in this field and the future impacts they may have.…”

Compósitos de HDPE com resíduos de fibras têxteis. Parte I: caracterização mecânica

“…Uma alternativa que tem sido proposta para minimizar o problema é o desenvolvimento de materiais obtidos a partir de fontes renováveis, tais como compósitos formados de fibras naturais [1] . A utilização de fibras naturais como reforço em polímeros termoplásticos tem sido estimulada também devido ao elevado custo ambiental de se produzir fibras sintéticas, que possuem maior conteúdo energético devido ao processo de fabricação [2] , tais como vidro, carbono e Kevlar® [3] , além de considerar aspectos relacionados à biodegradação [4] .…”

“…Todas as fibras vegetais, como algodão, juta e sisal têm celulose em sua composição, enquanto fibras de origem animal, tais como lã e seda, consistem basicamente de proteínas [4] . As vantagens de se utilizar fibras naturais em relação a materiais tradicionais reforçantes, tais como fibras de vidro, talco e mica, são: baixo custo; alta tenacidade; boas propriedades mecânicas e térmicas; redução do desgaste de máquina; facilidade de separação e biodegradabilidade, dentre outras.…”