Preparation, Thermal, and Mechanical Characterization of UV-Cured Polymer Biocomposites with Lignin.

Marta Goliszek,Tomasz Klepka,Beata Podkościelna,Olena Sevastyanova

doi:10.3390/polym12051159

Abstract

The preparation and the thermal and mechanical characteristics of lignin-containing polymer biocomposites were studied. Bisphenol A glycerolate (1 glycerol/phenol) diacrylate (BPA.GDA) was used as the main monomer, and butyl acrylate (BA), 2-ethylhexyl acrylate (EHA) or styrene (St) was used as the reactive diluent. Unmodified lignin (L) or lignin modified with methacryloyl chloride (L-M) was applied as an ecofriendly component. The influences of the lignin, its modification, and of the type of reactive diluent on the properties of the composites were investigated. In the biocomposites with unmodified lignin, the lignin mainly acted as a filler, and it seemed that interactions occurred between the hydroxyl groups of the lignin and the carbonyl groups of the acrylates. When methacrylated lignin was applied, it seemed to take part in the creation of a polymer network. When styrene was added as a reactive diluent, the biocomposites had a more homogeneous structure, and their thermal resistance was higher than those with acrylate monomers. The use of lignin and its methacrylic derivative as a component in polymer composites promotes sustainability in the plastics industry and can have a positive influence on environmental problems related to waste generation.

Highlights

Epoxy resins are among the most important materials in the modern polymer industry [1,2,3,4,5,6,7,8,9,10].They can be further reacted to form thermoset polymers with a strong adherence to many substrates, a great thermal resistance, good electrical and mechanical properties, a low order of shrinkage on cure, a high degree of chemical and solvent resistance, and a moderate cost [11,12,13,14]
When a mixture of BPA.GDA, reactive diluent, and unmodified lignin was subjected to UV radiation in the presence of photoinitiator, composites of various thickness could be prepared despite the well-known radical scavenging and UV-inhibiting properties of the phenolic groups in lignin [50,51,52,53,54,55,56] (Figure 1d–f)
In which most of the phenolic groups are substituted by vinyl groups, was used as a component of the system, UV-initiated polymerization readily occurred on the surface of the composite, leaving the core unreacted

Summary

Introduction

Epoxy resins are among the most important materials in the modern polymer industry [1,2,3,4,5,6,7,8,9,10] They can be further reacted to form thermoset polymers with a strong adherence to many substrates, a great thermal resistance, good electrical and mechanical properties, a low order of shrinkage on cure, a high degree of chemical and solvent resistance, and a moderate cost [11,12,13,14]. Difunctional acrylates are used as Polymers 2020, 12, 1159; doi:10.3390/polym12051159 www.mdpi.com/journal/polymers

Methods

Results

Conclusion