The pultrusion process allows production of fiber-reinforced polymer profiled shapes of continuous lengths. First, fiberglass in the form of continuous fiber bundles is drawn though a liquid resin, which saturates the glass reinforcement. The combination of resin and glass is then pulled through a special die using a continuous pulling device. The mass of materials conforms to the shape of the die and is set into a permanent, structurally reinforced shape. The resulting high-strength profile is cut to the desired lengths and is thereafter ready for use. Pultruded products provide manufacturers and designers with the benefits of high strength-to-weight ratios, corrosion resistance, heat resistance, dielectric properties, dimensional stability and weatherability.
Since the PROWASTE RPL (Recycled Plastic Lumber) material includes fibre-glass rods for reinforcement, this material falls into the reinforced RPL type of pultruded rods. These rods are expected to have enhanced structural characteristics with respect to conventional RPL as well as having higher strength and rigidity, which will allow the design of end-products able to withstand higher load conditions. Thanks to the fibre-glass rods as reinforcement, the RPL from this project will also have lower profile dimensions which may also bring a decrease in total lumber (thus also final product) weight. Other advantages are considerable enhancement of flexural stiffness and creep resistance and greater aesthetic features. There is also a possibility to use the new plastic lumber for innovative applications where weight and bending properties are important issues (such as pallets and railway ties).
Additionally, the reinforced rods from the project also have a decreased environmental impact with respect to conventional RPL, since they are made from scrap waste generated during the sorting process of plastics waste, thus avoiding landfilling or incinerating this waste.
The rods have been subject to a number of test, with the following results:
- Bending tests showed that the incorporation of glass fibre reinforced rods in the plastic lumber beams improves the flexural stiffness by factor of 2.
- Pull-out tests showed that sandblasting increases the interfacial adhesion stress between plastic lumber and rods by one order of magnitude.
- Cyclic loading tests showed that the beam reinforced with sandblasted rods had a residual deflection one order of magnitude lower than that corresponding to unreinforced beam.
- Creep tests showed that the incorporation of rods decreases the material creep compliance, which results more than one order of magnitude lower than that corresponding to unreinforced beam.
“Advances in Polymer Technology”, vol. 27, No. 3, 133-142 (2008)- 2009 Wiley Periodicals, Inc.