The Preparation And Property Characterization Of Temperature Sensitive Hydrogel

Functional thermoregulation textiles have become more and more important in modern life,and the temperature-sensitive hydrogel is usually used to achieve the thermoregulation function.In this paper,copolyester was prepared with polyoxyethylene lauryl ether(MOA)and acrylic acid.MOA has four different polymerization degrees.Cross-linked hydrogels were treated with the function of initiator and crosslinker agent when copolyester,acrylic and n-butyl acrylate acted as monomers.Furthermore,the chemical structures of polymerized monomers and hydrogels were investigated by FTIR and XRD analysis methods.Finally,the influence of external conditions on the hydrogels' properties with different proportions and polymerization degrees was discussed.The external conditions include content of crosslinker agent,initiator and the concentration of NaOH solution.By using FTIR method,it shows the intensity of the same peak increases with the increase of MOA polymerization degree.The majority of peaks location shift to larger wave numbers.When characterizing the polymerization degrees,it shows the peak ratios from All 14/A885 and A952/A885 are ideal.The content of hydrophobic groups-methylene bonds is higher than hydrophilic groups-vinyl ether bonds in MOA.X-ray diffraction shows that the hydrogels are amorphous polymers.The shapes of infrared spectra between MOA3 and MOA4 hydrogel are similar,as well as MOA7 hydrogel and MOA9 hydrogel.With the increase in polymerization degree of MOA,the content of acrylic acid in hydrogels increases accordingly.The completeness of hydrogels is better and the implosion becomes less.When the degree decreases,the hydrogels shrink more seriously and their colors become deepen.When the percentage of monomers are 1:1:1,the crosslinker content(>2%)has little effect on the conversion rate of the polymerization reaction.Whereas the conversion rate decreases when the initiator content increases(?0.5%)?In the swelling test,it has proved the swelling property is the best when the crosslinker content is 2%.The swelling ratio decreases when the initiator content increases.The best condition of hydrogels' swelling property is 2%crosslinker content and 0.5%initiator content.Furthermore,the hydrogels swell desirably when the concentration of NaOH solution is 0.1%.They follow the same model in the initial swelling process.The content of crosslinker and initiator has no effect on the temperature-sensitive property of hydrogels.When the polymerization degrees of the four kinds of hydrogels increase,the phase inversion temperature moves to the high temperature.The phase inversion temperature difference between the above-mentioned method and the way of judging from the chage of hydrogels transparency can be limited within 5 centigrade degree.With the crosslinker content increase,the strength of dry and swelling hydrogels increase gradually.If the crosslinker content is the same,with the increase of degree,dry hydrogels,strength declines and the strength of swelling hydrogels increases.Mostly,the two kinds of hydrogels strengh decreases when the initiator content increases.When the initiator content is the same,the strength of dry hydrogels decreases and the swelling hydrogels' strength increases with the polymerization degree increase.For the different swelling hydrogels,with the swelling degree increase,there is an increase trend in the strength of MOA3 hydrogel and MOA4 hydrogel.However,MOA7 hydrogel strength increases firstly and then declines.MOA9 hydrogel strength follows the tendency of increase,decrease and increase.