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

Waste accumulation has grown significantly. For example, the construction sector is a significant producer of waste. We must find a practical way to exploit this valuable pro material strain.

Construction and demolition waste includes plastic, valuable raw material for wood-polymer composites. This recycled plastic can be substituted for wooden polymers if it's able to be properly identified and processed. To identify polymers in plastic contact the polymer of interest with a portable near infrared spectroscopy tool in the 1600 to 2400 nanometer spectral range and determine the type of polymer by the measured reflectance.

Use the spectroscopy identification curve to analyze the laboratory results and sort the materials between the polymers based on the identification results. To perform size reduction for the selected plastic materials place the identified and collected material into a single shaft shredding system equipped with a crusher shredder apparatus and crush the plastic materials at a low speed crush and with a five millimeter shiv. When the material is homogeneous measure the material amounts for the composites and present the materials in their relative amounts of plastic, wood, coupling agent, and lubricant.

For wood-polymer composite material processing with extrusion technology, after size reduction treatment mix all of the components of the process in a turbo mixer and cooler apparatus and agglomerate the materials in the turbo mixer until the temperature of the materials reaches 200 degrees Celsius. Due to the combined effects of temperature and friction granule materials will be formed at the end of the treatment. At the end of the treatment cool the materials for four to seven minutes in a cooler apparatus before evacuating the material from the processor and collecting the agglomerated material.

In the control panel of the extrusion machine set the average barrel temperature to between 167 and 181 Celsius and the average tool temperatures to between 183 and 207 degrees Celsius. The melt temperature should be set between 164 and 177 degrees celsius. And the dye pressures should be between 3.7 and 5.9 megapascals.

Adjust the parameters as necessary. As recycled material are heterogeneous and the process requires professional control. And use a conical counter rotating twin screw extruder with a 15 kilogram per hour material output to compound the components.

After the extrusion process the profile material of the composite can be generated. To prepare samples for a flexural property test use a sliding table saw to cut 800 by 50 by 20 millimeter samples from the extruded profiles. For a tensile property test use the computer numerical controls to set the material performs to a dumbbell shape and cut 150 by 20 by four millimeter samples from the extruded materials.

To saw test samples from the extruded materials for an impact strength test use the sliding table saw to cut the samples into 80 by 10 by four millimeter pieces. Then place the test material into a 23 degree celsius and 50%relative humidity condition chamber until a constant mass is reached. To perform a flexural strength and modulus test for each of 20 samples place a flexural test sample in the testing apparatus at the support of two points and click test start to apply a preload of 15 newtons and a test speed of 10 millimeters per minute to the center of the sample.

The test will stop automatically after recording the result. Remove the sample from the support tools and place a new sample onto the tools. To perform a tensile strength and modulus test for 20 machined dumbbell shaped samples set the tensile test sample between the test tools and attach noematic clamps to keep the sample in the tools during the test.

Start the test from the computer control panel with a preload of 10 newtons and a test speed of two millimeters per minute and attach and extension meter tool immediately after the test start. At the end of the rest remove the test sample and set a new sample on the tools. To perform an impact strength test place a 10 by four millimeter sample between the supports of an impact tester and reset the force.

Then release the impact hammer at an impact force of five kilapond centimeters. When all of the tests have been completed calculate the average value for each set of tested samples. To investigate the effects of construction and demolition waster plastic polymer on the mechanical properties of wood polymer composites three different polymer types were studied as a matrix using three different processing parameters.

The highest flexural strength values were achieved with the material containing a recycled ABS polymer in a matrix. and and almost congruent high strength quality was achieved in the material in which recycled polyethylene polymer was used in a matrix. The lowest flexural strengths were achieved with the material containing a recycled polypropylene polymer in a matrix.

Similar results are also observed for the flexural modulus of materials which was measured simultaneously with the strength property. With the recycled polyethylene materials exhibiting a significantly lower modulus value compared to the value of the recycled ABS polymer. The materials which used recycled ABS and polyethylene have an almost congruent tensile strength.

While the weakest tensile strength was achieved with the material containing a recycled polypropylene polymer in a matrix. Similar results were observed for the tensile modulus analysis. Further, the impact strengths of the recycled ABS and polypropylene polymers were almost the same.

But a greater impact strength was achieved with the recycled polyethylene polymer which had the best impact strength property in this study. It is important to ensure that materials are identified and sorted before the processing and to model correct material ratio of all materials before the manufacturing steps. Using this protocol as demonstrated several other functional properties such as moisture resistance and strength after cycle treatment can also be investigated.

As demonstrated, waste materials can be reutilized as raw material. In future studies, new raw material stream should be evaluated and their properties should be tested in novel products.