The Effect of Construction and Demolition Waste Plastic Fractions on Wood-Polymer Composite Properties

Summary

Secondary material streams have been shown to include potential raw materials for production. Presented here is a protocol in which CDW-plastic waste as a raw material is identified, followed by various processing steps (agglomeration, extrusion). As a result, a composite material was produced, and mechanical properties were analyzed.

Abstract

Construction and demolition waste (CDW), including valuable materials such as plastics, have a remarkable influence on the waste sector. In order for plastic materials to be re-utilized, they must be identified and separated according to their polymer composition. In this study, the identification of these materials was performed using near-infrared spectroscopy (NIR), which identified material based on their physical-chemical properties. Advantages of the NIR method are a low environmental impact and rapid measurement (within a few seconds) in the spectral range of 1600-2400 nm without special sample preparation. Limitations include its inability to analyze dark materials. The identified polymers were utilized as a component for wood-polymer composite (WPC) that consists of a polymer matrix, low cost fillers, and additives. The components were first compounded with an agglomeration apparatus, followed by production by extrusion. In the agglomeration process, the aim was to compound all materials to produce uniformly distributed and granulated materials as pellets. During the agglomeration process, the polymer (matrix) was melted and fillers and other additives were then mixed into the melted polymer, being ready for the extrusion process. In the extrusion method, heat and shear forces were applied to a material within the barrel of a conical counter-rotating twin-screw type extruder, which reduces the risk of burning the materials and lower shear mixing. The heated and sheared mixture was then conveyed through a die to give the product the desired shape. The above-described protocol proved the potential for re-utilization of CDW materials. Functional properties must be verified according to the standardized tests, such as flexural, tensile, and impact strength tests for the material.

Introduction

Global waste generation has grown significantly throughout history and is predicted to increase by tens of percentages in the future unless action is taken¹. In particular, high-income countries have generated more than one-third of the world’s waste although they account for only 16% of the global population¹. The construction sector is a significant producer of this waste due to rapid urbanization and population growth. According to estimates, approximately one-third of global solid waste is formed by construction and demolition projects; however, exact values from different areas are missing²

Protocol

1. Identification and pre-treatment

1. Identify polymers in plastic with the portable near-infrared (NIR) spectroscopy tool in the spectral range of 1600–2400 nm. Contact the polymer with spectroscopy tool and determine the polymer by the measured reflectance.
   1. According to the identification curve of spectroscopy, analyze the identification results from the screen in the laboratory.
2. Based on the identification result, sort materials between the polymers and measure their.......

Discussion

The mechanical properties of WPC play an important role in deciding the suitability of these products in various applications. WPC consists of three main ingredients: plastic, wood, and additives. The mechanical properties of fiber-based composites depend on the length of the used fiber, where “critical fiber length” is the term used to indicate sufficient reinforcement²⁵. In addition to the properties of ingredients, the quality of raw materials is the important factor for the perform.......

Materials

Name	Company	Catalog Number	Comments
Agglomeration	Plasmec	TRL100/FV/W	apparatus of turbomixer
Agglomeration	Plasmec	RFV 200	apparatus of cooler
CNC router	Recontech	F2 - 1325 C	CNC machine
Condition chamber	Memmert	HPP260	constant climate chamber
Coupling agent	DuPont	Fusabond E226	commercial coupling agent additive
Crusher 1 (crusher/shredder )	Untha	Untha LR 630	10-20 mm sieve
Crusher 2 (low-speed crusher)	Shini	Shini SG-1635N-CE	5 mm sieve, granulator
Extruder	Weber	Weber CE 7.2	conical counter-rotating twin-screw
Lubricant	Struktol	TPW 113	commercial lubricant additive
NIR spectroscopy	Thermo Fisher Scientific	Thermo Scientific microPHAZIR PC
Recycled material ABS from CDW
Recycled material PE from CDW
Recycled material PP from CDW
Sliding table saw	Altendorf	F-90	circular saw/sliding table saw
Testing apparatus	Zwick	5102	impact tester
Testing machine	Zwick Roell	Z020	allround-line materials testing machine
Wood flour (Spruce) material
WPC example material	UPM Profi		Decking board