Development of recycled polymer blends for thermal spray applications

A proposed rule to implement Section 183(e) of the Clean Air Act amendments (1990) will further restrict the volatile organic compound (VOC) content of rust-preventing coatings. Thermal spray polymers represent one option for protecting steel structures while complying with the new VOC restrictions. Thermal spray technology can apply polymer coatings to many different substrate materials at various thicknesses and under wide range of ambient conditions. Potential benefits of thermal spray polymers could be extended by blending post-consumer commingled polymers (PCCP) into coating feedstock materials; thermal spray polymers have the potential both to lower material costs and reduce the volume of the solid waste stream. This research investigated and demonstrated high-molecular weight and commingled/post-consumer recycled polymer blends as low-VOC thermal spray coatings. It is concluded that the incorporation of PCCP into virgin thermal spray polymer is associated with some loss of coating performance. Also, cost savings resulting from blending 25 percent PCCP with 75 percent virgin polymer are insignificant compared to the total cost of a recoating job using other VOCcompliant systems. Therefore, the blends investigated here probably will not have significant commercial usefulness, and they are not recommended for corrosion protection of steel structures