| In order to solve the liquid flow and leakage problems of conventional solid-liquid phase change materials in the phase transition process,the development and research of solid-solid phase change materials came into being.Among them,polyurethane solid-solid phase change materials have become the focus of research because of their excellent and unique properties.However,most of the researched polyurethane solid-solid phase change materials have phase transition temperatures above 50?,resulting in great restrictions on their application in textile fiber materials.In this paper,starting from the molecular chain structure design,the block copolymerization method is adopted,and polyethylene glycol(PEG)and polytetrahydrofuran ether glycol(PTMG)are used as soft segment raw materials,respectively,and react with isophorone diisocyanate(IPDI),And then through a small molecule chain extender chain extension,aiming to develop a series of water-soluble polyurethane solid-solid phase change energy storage materials(WPUPCM)with a phase transition temperature of about 20?38?.Determine the chemical structure of WPUPCM by Fourier Infrared Spectrometer(FTIR),Thermogravimetric Analyzer(TG),Differential Scanning Calorimeter(DSC),analyze its thermal stability,characterize its heat storage performance,and pass polarized light microscope(POM),X-ray diffraction spectroscopy(XRD)observed WPUPCM crystalline state,characterized its crystalline properties.First,PEG-based WPUPCM was prepared with PEG as the soft segment and the reaction segment of IPDI and BDO as the hard segment.The effects of chain extension reaction temperature,PEG molecular weight,monomer molar ratio,and BDO dosage on the performance of WPUPCM are discussed.The results show that,when the temperature of the chain extension reaction is 70?,the reaction between the monomers is more sufficient,the prepared WPUPCM has a high thermal decomposition temperature and good heat storage performance;the WPUPCM prepared when the PEG molecular weight is 1000 does not have phase change performance,and the molecular weight is in the range of 2000?6000,The melting temperature,melting enthalpy,crystallization temperature and crystallization enthalpy of the phase change material increase with the increase of molecular weight.When the molecular weight exceeds 6000,the phase change temperature and phase change enthalpy decrease slightly;With the decrease of PEG content,the melting temperature and melting enthalpy of WPUPCM decrease,the thermal decomposition rate increases,and the crystallization performance decreases,and only when the content of PEG2000 does not exceed 85.23%and the content of PEG3000 does not exceed 88.81%WPUPCM prepared with PEG2000 and PEG3000 as the soft segment only exhibits solid-solid phase transition characteristics;Changing the type of chain extender found:WPUPCM with the same PEG content,glycerol(GL)chain extension has a lower melting temperature and higher melting enthalpy than BDO chain extension.When the content of PEG2000 is 65.10%?79.83%,the melting temperature can be prepared A series of WPUPCM with melting enthalpy between25.81?35.19?and 20.31?80.10J·g-1.Then,PTMG-based WPUPCM was prepared with PTMG as the soft segment.By investigating the influence of the three chain extenders BDO,GL and DMPA on the emulsification performance of PTMG-based WPUPCM,it was determined to choose the hydrophilic chain extender DMPA to prepare PTMG-based WPUPCM.The effect of synthesis conditions on the reaction rate and degree of reaction was studied,and the preparation process of PTMG-based WPUPCM was determined:prepolymerization temperature 80?for 2.5h,chain extension temperature 80?for 2h.The phase change temperature and phase change enthalpy of PTMG-based WPUPCM with PTMG content and DMPA dosage are similar to PEG-based WPUPCM.The study also found that although the phase transition temperature of the PTMG-based WPUPCM is low,the phase transition enthalpy is also low,and the temperature regulation capability is limited.In order to obtain WPUPCM with good application effects,a series of WPUPCM with different PEG/PTMG mass ratios were prepared by using PEG/PTMG as the composite soft segment.The study found that when the chain extension of BDO is performed,when the mass ratio of PEG to PTMG is changed,two peaks will appear in the heating and cooling process of WPUPCM,namely two peaks,?peak and?,and the?peak will increase with the increase of PTMG Large,?peak will decrease with the decrease of PEG content,When the content of PEG is less than 10g or the content of PTMG is less than 3g,the two peaks will merge into one peak;Using PEG/PTMG(proportion 27/3)compound as the soft segment,when GL chain extension is used to prepare WPUPCM,changing the molar ratio of the reaction monomer can prepare a melting temperature of 22.18?37.18?and a melting enthalpy of 20.19?8.24J·g-1 series WPUPCM.Finally,the prepared WPUPCM emulsion was put into pure cotton fabric to prepare intelligent temperature-adjusting fabric with temperature-adjusting performance.Scanning electron microscope was used to observe the fabric before and after finishing,and the mechanical properties of the fabric were tested.The actual temperature-adjusting performance of the temperature-adjusting fabric was studied using differential scanning calorimeter and temperature recorder.Electron micrographs show that polyurethane deposits a film on the surface of the fiber,making the surface of the fabric fiber wrapped with a smooth,smooth polyurethane film.Finishing cotton fabrics with different amounts of finishing agent,the weight gain rate increases with the increase of the amount of polyurethane emulsion,but too high amount of finishing liquid will cause the air permeability of the finishing fabric to decrease greatly and the fabric feel will change difference.The addition of softener can improve the feel of the tempered fabric.The results of the washing resistance of temperature-adjusted fabrics show that the increase in the number of washings reduces the heat retention rate of the finished fabrics,which reduces the temperature-adjusting ability of the finished fabrics.The type is high,and the washing resistance is better.After 30 washings,the two temperature-adjusting fabrics still retain good heat storage performance.In addition,the temperature-adjusting fabric has a significant buffer effect on temperature changes,and has a good heat storage and temperature-adjusting effect. |
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