Polyurethane Solid - Solid Phase Change Material Preparation And Characterization

Polyurethane phase change material (abbreviated as PUPCM) is the current phase change materials research in the field of an important research subject.In this thesis, starting from the molecular chain structure design, the method of prepolymers were prepared by polyethylene glycol (PEG)-based PUPCM, poly adipic acid ester (PAA) base PUPCM, and polyethylene glycol/poly adipic acid ester (abbreviated as PEG/PAA) mixed soft segment PUPCM. Through Fourier transform infrared spectroscopy (FTIR); thermal analysis (TG) analysis; dynamic mechanical analysis (DMA), hardness test, tensile strength testing and others to inspected the material mechanics performance and soft segments of the influence of raw material PUPCM performance are analyzed; Through polarized light microscopy (POM), XRD, atomic force microscope (AFM) test, carried the observation of microcosmic structure, analyzes the material microfacies separation structures, and the hard segment on soft segments two sides effect, discusses the mechanism of PUPCM phase.The main results are:It was investigated that in PUPCM system, only when mpeg weight molecular higher than 2000 as soft paragraph preparation phase of polyurethane materials, the polyurethane has a phase change feature. And hard segment content function must over 9%, the material show solid-solid phase transition performance. Results from DSC test showed that the phase transition temperature and phase transition enthalpy increased with the PEG molecular weight increased. But if the PEG molecular weight higher than 20,000, the phase transition enthalpy was slightly decreased. The best thermal performance when the molecular weight of 6000. Material phase change temperature increased with the mass fraction mpeg increase.And when the content of hard segment increasing, the stiffness of a material increased, but its tensile strength decreased.PAA-based PUPCM showed the same trend of thermal diffusivity, specific heat capacity and thermal conductivity with the soft segment content with the PEG-based PUPCM. But when the PAA-based PUPCM at a temperature below the phase transition temperature, the thermal conductivity coefficient of PEG content was higher than the same percentage of base PUPCM, and at a temperature above the phase transition temperature, thermal conductivity coefficient is lower than the same percentage of the content of PEG based PUPCM. The enthalpy of PAA based PUPCM was lower than PEG based PUPCM of the same soft segment content enthalpy PUPCM, hardness, tensile strength is higher than the PEG based PUPCM, dynamic mechanical properties superior to PEG based PUPCM. Despite the incompatible PEG and PAA causes PEG/PAA mixed soft segment PUPCM is non-uniform system, material appeared statified, but its phase transition temperature range widened. In combination with polyurethane materials structure model, explained the essence of PUPCM phase change materials and soft segments amorphous-the transition between the wuding patterns, including because of the hard segment taken the binding effect of soft segment to ensure that the material presented macroscopic solid-solid phase transition.