Obtaining ultra-high transmission of UHMWPE by hot uniaxial pressing for long-wave infrared imaging

•UHMWPE based flat plates were fabricated by Hot Uniaxial Pressing method for long-wave infrared imaging.•Both hot-pressing temperature and cooling rate could affect the transmittance of polymeric flat plate in LWIR spectrum.•The ultrahigh transmittance of 77 % (@ 10.5 μm) can be derived from 0.5 mm thick UHMWPE based flat plate. Although the numerous advantages of germanium or chalcogenide glasses have been applied in the long-wave infrared (LWIR) imaging (8–12 μm), the organic materials with low-cost and easy-fabrication advantages also received widespread attention in recent years. One thing that should be mentioned is that nearly all organic-based materials exist the abundance of vibrational absorptions within the 8–12 μm spectral region. Ultra-High Molecular Weight Polyethylene (UHMWPE) exhibits simplified LWIR spectrum in 8–12 μm due to the presence of only single-bonded carbon and hydrogen -(CH2)n-. In this paper, we prepared UHMWPE based flat plates by Hot Uniaxial Pressing (HUP) method. Therein, the effects of hot-pressing temperature and cooling rate on the transmission were investigated to find that the transmission is close to the crystallinity of the polymeric flat plate. We optimized an UHMWPE based flat plate with ultrahigh transmittance (∼77% @ 10.5 μm), which was fabricated at the hot-pressing temperature of 190 °C with the cooling rate of 1 °C min−1. The ultrahigh transmittance of the polymeric flat plate, which was obtained from low-cost UHMWPE and easy-fabrication of HUP, makes it be a candidate for LWIR imaging.