A New Approach to Chemical Recycling of Polyamide 6.6 and Synthesis of Polyurethanes with Recovered Intermediates

Janusz Datta,Kamila Błażek,Marcin Włoch,Radosław Bukowski

doi:10.1007/s10924-018-1314-4

Abstract

A new efficient method for the chemical decomposition of polyamide 6.6 by the glycolysis and amino-glycolysis processes was proposed. The glycolysis was conducted using the mass excess of ethylene glycol (EG) as a decomposing agent in the presence of a catalyst. Also, a mixture of EG and triethylenetetramine was used as another decomposing agent in the amino-glycolysis process. The described process of decomposition did not require the use of elevated pressure. The hydroxyl and amine numbers, rheology behavior and the presence of characteristic chemical groups in the obtained glycolysates and aminoglycolysates were determined in order to characterize the reaction products. The decomposition products were defined as non-Newtonian fluids that could be described by suitable mathematical models. The conducted studies showed that the properties of the obtained intermediates depend on the mass excess of the decomposing agent used. The resulting semi-products are suitable for reusing in the synthesis of polyurethanes, which has been confirmed by the exemplary synthesis. In the reaction, 10 and 15 wt% of commercial polyol were replaced with the recovered intermediates.

Highlights

It is commonly known that the amount of plastic waste has increased considerably over the last few years
The solid samples were obtained as a result of amino-glycolysis, while the samples resulting from the glycolysis reaction were in the liquid state
This finding is undoubtedly favorable because the obtained compounds can be used in the synthesis of polyurethanes

Summary

Introduction

It is commonly known that the amount of plastic waste has increased considerably over the last few years. In 2015, the global polymer production was estimated at 322 million tons per year [1]. This is due to the fact that plastics find use in a wide range of industrial applications, e.g. packaging, electrical and electronic industries, medicine, building and construction, motorization, and much more. The most common types of polyamide are obtained in the form of fibres or thermoplastics [6]. The hydrolytic route (ring-opening polymerization) is used to form polyamide 6, while polyamide 6.6 is obtained via stepgrowth reactions between diamines and diacids [8]. In order to improve the properties of aliphatic polyamides, the incorporation of aromatic moiety into an aliphatic backbone is

Methods

Results

Conclusion