A New Kind of Shape-stabilized Phase Change Materials

Based on the lowest melting point and Schroeder’s theoretical calculation formula,nano- modified organic composite phase change materials（PCMs）were prepared.The phase transition temperature and the latent heat of the materials were 24℃and 172 J/g,respectively.A new shape-stabilized phase change materials were prepared,using high density polyethylene as supporting material.The PCM kept the shape when temperature was higher than melting point.Thus,it can directly contact with heat transfer media.The structure,morphology and thermal behavior of PCM were analyzed by FTIR,SEM and DSC.

Synergistic Effect of Atmospheric Pressure Plasma Pre-Treatment on Alkaline Etching of Polyethylene Terephthalate Fabrics and Films

Dyeing of PET materials by traditional methods presents several problems.Plasma technology has received enormous attention as a solution for the environmental problems related with textile surface modifications,and there has been a rapid development and commercialization of plasma technology over the past decade.In this work,the synergistic effect of atmospheric pressure plasma on alkaline etching and deep coloring of dyeing properties on polyethylene terephthalate（PET）fabrics and films was investigated.The topographical changes of the PET surface were investigated by atomic force microscopy（AFM）images,which revealed a smooth surface morphology of the untreated sample whereas a high surface roughness for the plasma and/or alkaline treated samples.The effects of atmospheric pressure plasma on alkaline etching of the structure and properties of PET were investigated by means of differential scanning calorimetry（DSC）,the main objective of performing DSC was to investigate the effect of the plasma pre-treatment on the T_g and T_m.Using a tensile strength tester YG065 H and following a standard procedure the maximum force and elongation at maximum force of PET materials was investigated.Oxygen and argon plasma pre-treatment was found to increase the PET fabric weight loss rate.The color strength of PET fabrics was increased by various plasma pre-treatment times.The penetration of plasma and alkaline reactive species deep into the PET structure results in better dyeability and leaves a significant effect on the K/S values of the plasma pre-treated PET.It indicated that plasma pre-treatment has a great synergistic effect with the alkaline treatment of PET.

Polyethylene glycol/polylactic acid block co‐polymers as solid–solid phase change materials

Phase change materials(PCMs)are promising thermal energy storage materials due to their high specific latent heat.Conventional PCMs typically exploit the solid–liquid(s–l)transition.However,leakage and leaching are common issues for solid–liquid PCMs,which have to be addressed before usage in practical applications.In contrast,solid–solid(s–s)PCMs would naturally overcome these issues due to their inherent form stability and homogeneity.In this study,we report a new type of s–s PCM based on chemically linked polyethylene glycol(PEG,the PCM portion)with polylactic acid(PLA,the support portion)in the form of a block co‐polymer.Solid‐solid latent heat of up to 56 J/g could be achieved,with melting points of between 44°C and 55°C.For comparison,PEG was physically mixed into a PLA matrix to form a PEG:PLA composite.However,the composite material saw leakage of up to 9%upon heating,with a corresponding loss in thermal storage capacity.In contrast,the mPEG/PLA block co‐polymers were found to be completely homogeneous and thermally stable even when heated above its phase transition temperature,with no observable leakage,demonstrating the superiority of chemical linking strategies in ensuring form stability.