Clean and Effective Lignin Upgrading Pathway as Green Polymer Feedstock: Strategies to Break Through the Restrictions of Lignin Heterogeneity

Recycling is a crucial area of research in green polymer chemistry. Various developments in recycling are driven by Environmental concerns, interest in sustainability and desire to decrease the dependence on non-renewable petroleum based materials. Polyurethane foams [PUF] are widely used due to their light weight and superior heat insulation as well as good mechanical properties. As per survey carried Polyurethane Foam Association, 12 metric tonnes of polyurethane foam are discharged during manufacturing and/or processing and hence recycling of PUF is necessary for better economics and ecological reasons. In present study, rejects of PUF is subjected to reaction with a diethylene amine in presence of sodium hydroxide [NaOH] as catalyst, as a result depolymerised product containing hydroxyl and amine groups is obtained. Conventional and Microwave reaction for depolymerizing polyurethane foam have been carried, and best results are obtained by Microwave reaction. Further depolymerised product with hydroxyl and amine functionalities are reacted with bis (2-hydroxyethyl terephthalate) [BHET] obtained by recycling polyethylene terephthalate [PET] and sebacic acid, with stannous oxalate [FASCAT 2100 series] as catalyst to obtain Polyester amides. These Polyester amides having hydroxyl and amino groups in excess are cured with isocyanates-hexamethylene diisocyanate biuret [HDI biuret] and isophorone diisocyanate [IPDI] for coating applications. The coated films are characterized using physical, mechanical and chemical tests, which shows comparable physical, mechanical properties but alkali resistance is poor.

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Green composites and their contribution toward sustainability: A review

Polymers and Polymer Composites ◽

10.1177/09673911211009372 ◽

2021 ◽

pp. 096739112110093

Author(s):

Edgar Vázquez-Núñez ◽

Andrea M Avecilla-Ramírez ◽

Berenice Vergara-Porras ◽

María del Rocío López-Cuellar

Keyword(s):

Natural Fiber ◽

World Market ◽

Raw Material ◽

Green Composites ◽

Green Materials ◽

Global Problems ◽

The Matrix ◽

Green Economies ◽

Green Polymer ◽

World Environment

The current world environment scenario demands new and more eco-friendly solutions to global problems that cover the demands for materials. This sector has included green polymer-based composites and natural reinforcers from origins of renewable sources, these Green Composites (GC), natural-fiber-reinforced bio-composites in which the matrix is a bio-based polymer, have shown attractive characteristics. Biodegradability is one of the most important attributes for these new “green” materials, in that this characteristic allows for their introduction into the world market as an environmental solution. The manufacturing processes for obtaining these materials have observed important improvements because each raw material exhibits different properties and characteristics and their eco-friendly character has facilitated its incorporation into diverse sectors, such as construction, automotive, packaging, and medicine, among others. At present, this segment represents an important income for some economies, especially those where these resources are available, enhancing the creation of green economies, strengthening the world’s efforts toward sustainability.

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