# Effects of Propylene Carbonate on the Properties of Epoxy Resin/Carbon Fiber Multilayer Material Used for Underwater Artifact Extraction

## TL;DR

This paper explores using propylene carbonate to improve epoxy resin for underwater artifact extraction, enhancing flowability and mechanical properties.

## Contribution

The novel use of propylene carbonate as a diluent to optimize epoxy resin properties for underwater archaeological applications is presented.

## Key findings

- Propylene carbonate extended gel time from 22 to 38 minutes with minimal effect on curing time.
- The E44/PC10 formulation showed good mechanical properties and successfully wrapped irregular artifacts.
- Multilayer materials with PC exhibited temperature stability and were used to extract waterlogged wooden artifacts from 13 m depth.

## Abstract

The use of epoxy resin/carbon fiber multilayer materials can effectively prevent damage to artifacts during underwater archaeological artifact extraction. However, the high viscosity of epoxy resin limits the coating ability and curing quality. To solve this problem, propylene carbonate (PC) was used as a diluent to reduce the viscosity and improve the properties. This study investigated the gel time, curing time, curing degree, and mechanical strength of the cured products by varying PC concentrations. It was found that the PC significantly enhanced the flowability of epoxy resin blends, extending the gel time from 22 min to 38 min, with minimal impact on the curing time. The glass transition temperature (Tg) ranged from 25.80 °C to 12.28 °C. Compared to E44/PC0, PC reduced the CTE values in the weft direction. The multilayer materials exhibited good temperature stability. The cured product had good mechanical properties and toughness, and could wrap irregular artifacts. The E44/PC10 formulation was used to prepare the epoxy resin/carbon fiber multilayer material. Waterlogged wooden artifacts were successfully extracted from 13 m deep calm water, using the multilayer material.