| abstract |
Polymer and wood composite structural members are manufactured by extruding and injection moulding a composition comprising polyvinyl chloride, wood fibre and optionally a concentration of an intentionally added waste stream. Such structural members have strength, workability, fastener retention, resistance to rot and insect attack, and thermal properties sufficient to constitute an advanced composite wood replacement material. The advanced structural member can be used as a component in construction of any structure requiring sized lumber or specifically shaped wood products. In such an application, the structural members can be extruded in the shape of commonly available lumber. The structural members of the invention can also be extruded in complex shapes adapted to the assembly of windows and doors used in both residential and commercial structures. The structural members have a modulus, a coefficient of thermal expansion, a coefficient of elasticity, a compressive strength and other related properties ideal for use as a replacement for either metal or wood, window or door structural components. The preferred structural member is manufactured from a polyvinyl chloride and wood fibre composite that optionally contains an intentionally recycled impurity component. Such components comprise waste materials common in the manufacture of wood doors and windows. The cooperation between the amount of polymer material, the amount of an oriented wood fibre, and control over water content results in improved structural properties. |