Environmental impact of compostable polymer materials

Used parameters in environmental impact analysis include resource consumption, energy consiunption, total waste production, greenhouse gas emissions, regulated air pollutants release, 

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Chapter 8 describes the environmental impact of compostable polymer materials, including life cycle anatysis (LCA). 

The composting test method based on activated vermicuUte was proposed as a comprehensive system for the assessment of the environmental impact of compostable polymers [1, 2]. Vermicnlite, a clay mineral, can be activated (by an inoculation with an appropriate microbial population and fermentation) and used as a sohd matrix in place of mature compost in the controlled composting test. The formula of vermicnlite is (MgJ e,Al)3(Al,Si)40io(OH)2.4H20. The results obtained with two materials (cellulose and a starch-based blend) indicated that activated vermicnlite affected neither the biodegradation rate nor the final biodegradation level. 

Safety considerations where the resultant compost should have no impact on plants, using the Organisation for Economic Co-operation and Development Guide 208, Terrestrial Plants Growth Test. Furthermore, the regulated (heavy) metals content in the polymer material should be 50% or lower than prescribed thresholds in the country of use (e.g., 50% in the US and in the Canadian Environmental Protection Agency s prescribed threshold). 

For this purpose, the quality rules for biodegradable polymers have to be strict and guarantee, besides compostability and biodegradability in different environments, nontoxicity of products and additives, as well as a low environmental impact throughout the life cycle, with improving targets in terms of raw material quality and renewability level, feedstock sustainability, inuse efficiency and end of life options to close the loop. 

Cellulosic natural fibers (e.g., abaca, bamboo, jute, flax, and hemp) have long been used as load-bearing materials to reinforce polymer matrix. Compared to traditional reinforcement fibers, for example, glass fibers and carbon fibers, cellulosic fibers show the advantages of low material cost, low environmental impact (renewability and carbon dioxide neutral, i.e., no excess carbon dioxide is returned to the environment when composted or combusted), and competitive strength/density ratio [31]. Cellulosic fibers are almost nonabrasive to processing equipment, which contributes to substantial reduction in production cost. They are also safer to handle compared to manmade fibers. 

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