Cold-Pressed Insulation Boards from Recycled Cotton Fibers Using a Water-Borne PVAc–Starch Binder: Processing, Structure and Properties

TL;DR

Researchers made eco-friendly insulation boards from recycled cotton using a low-temperature process and a starch-based binder, achieving good thermal and mechanical properties.

Contribution

A new low-temperature method for making insulation boards from recycled cotton fibers using a water-based PVAc–starch binder is introduced.

Findings

Insulation boards had thermal conductivity values between 0.0710 and 0.0739 W·m−1·K−1.

Compressive strength ranged from 46 to 162 kPa at 10% deformation.

Water absorption decreased by 18% with higher board density.

Abstract

This study investigates the valorization of post-consumer and post-industrial recycled cotton fibers from textile waste into porous fiber-based insulation composites using a low-temperature cold-pressing process and a water-borne hybrid binder based on polyvinyl acetate (PVAc) and modified cornstarch. Insulation boards were produced with target densities ranging from 300 to 340 kg·m−3, achieved by systematically adjusting the percentage weight fractions of recycled cotton fibers and binder components. The influence of board density on microstructure, inter-fiber bonding, and structure–property relationships was evaluated. The resulting boards exhibited thermal conductivity values between 0.0710 and 0.0739 W·m−1·K−1. Compressive strength measured at 10% relative deformation of the specimen thickness ranged from 46 to 162 kPa, while internal bond strength varied between 2 and 6 kPa. Water absorption decreased by approximately 18% with increasing density, indicating improved binder distribution and reduced open porosity. The PVAc–starch binder system enabled effective inter-fiber bonding without formaldehyde-based resins or energy-intensive curing, supporting a low-temperature and circular processing concept for textile waste valorization. Overall, the results demonstrate that recycled cotton fibers represent a viable feedstock for porous insulation composites combining balanced thermal, mechanical, and moisture-related performance with potentially reduced environmental impact.

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