Mingyuan Hu, Dongming Yu, Zhangcheng Chen, Cheng Zhi, Kaige Duan
Papers # 2018 Las-Vegas
Studying in barrier property of TLCP/PO alloy and EVOH/PO alloy. Filtrating formulas with extruding alloy into pipes. Trying to coat alloy on pipes and co-extrude into two-layer oxygen barrier plastic pipe.
The traditional Ethylene vinyl alcohol copolymer (EVOH) barrier plastic pipe used in internal closed-loop hydronic heating systems is three or five layers, which has complex structure and may be separated. Thermotropic Liquid Crystal Polymer (TLCP) is a new type of barrier material. The oxygen permeability of TLCP is only one-tenth of EVOH. When EVOH or TLCP is used as barrier layer, the waste/scrap can’t be recycled because EVOH or TLCP is not compatible with work layer. The thermotropic liquid crystal also has some machining difficulties such as higher processing temperature, smaller melt viscosity and obvious orientation. EVOH/PO(polyolefins) alloy and TLCP/PO alloy can be used as high barrier material layer, which can be extruded with the thermoplastic working layer such as PERT and PB, to form two layer structure oxygen barrier pipe. Choosing the polyolefins which has the same or similar material with work pipe, so that adhesive layer can be eliminated, separating will not be easy and the scrap can be processed directly to the machine. This subject has been preliminarily made EVOH/PERT alloy, EVOH/PP alloy, TLCP/HDPE alloy and TLCP/PP alloy. The oxygen permeability of EVOH/PERT is only 2.4 times of EVOH, and one percent of PERT; The vicat softening temperature can reaches 130.90℃, which has good heat resistance; in addition it keeps compatible with polyolefins.
