| After finishing with shape memory emulsions cotton fabrics have shape memory effect,that is,it has not only excellent elasticity but also good shape memory effect in terms of temperature sensitivity.The shape memory effect has improved wrinkle recovery and crease retention.As environment temperature being in about switch temperature it will recover to flat appearance after the fabrics shaped with flat appearance being wrinkled or deformed by wearing,washing or storing a long time.And it will recover to crease appearance after the fabrics shaped with crease appearance becoming flat by the same situation.The wrinkle recovery angle and flat appearance and crease retention increase significantly after the fabric finished.Improvement of the wrinkle recovery angle of fabrics finished indicate the elasticity of fabrics increasing,while increasing of flat appearance and crease retention of shape memory fabrics demonstrate that shape memory effect has been embedded in the fabrics.In this paper the influence of shape memory finishing process on tensile and tearing strength and wrinkle recovery of fabrics were discussed. An attempt has been made to investigate the influence of switch temperature on wrinkle recovery.An experimental investigation of the relationship between recovery and physical properties of shape memory fabrics finished has also been reported.By means of Kawabata Evaluation System(KES) the bending,surface and compression were discussed for fabrics finished and unfinished as well as fabrics washed and unwashed, and by means of Fabric Eye the evaluation of fabric appearance such as surface area,thickness,volume,roughness and even were analyzed for those.The method and effect to improve the weft strength of fabrics finished also were explored. It shows that the dosage of chemicals influence the performance of the samples.The reasonable concentration of shape memory emulsion is about 60g/L.The finishing process such as pre-wetting and steaming as well as the order of pressing and curing could influence the strength of the samples, but the effect is not obvious.However,dimension stability and flat appearance of fabrics finished are obviously improved by pre-wetting and steaming,and wrinkle recovery angle of fabrics is higher by curing and then pressing process.It was observed that the influence of wash temperature after finishing is not obvious on flat appearance and crease retention of fabrics.Shape memory effect is affected by weave.Because using the same chemicals and process the recovery behavior of two kinds of fabrics are different.After finishing wrinkle recovery angle of twill was improved more than that of plain,which the former increased 69%to106% and the latter increased 48%-57%.The results reveal that the shape memory fabrics exhibit good wrinkle recovery,flat recovery and crease retention after repeated laundering and drying at about 60℃(switch temperature),which some fabrics finished had better wrinkle recovery after washed over 30 times,this is,perhaps,may be called as shape memory effect.The shape memory emulsions can significantly improve WRA,thus the elasticity of finished cotton fabrics,probably through grafting onto the fibre surface to form interfibre and interyarn bonds.There exists a positive correlation between WRA and the flat appearance ratings,which indicate that as the wrinkle recovery angle increase,the flat appearance ratings also increase showing a better recovery of the flat shape.The correlation coefficient between the two was around 0.78.The flat appearance ratings express the flatness of finished fabric which was earlier wrinkled and recovered in the washing and drying processes affected by water and temperature whereas,the WRA indicates the degree of recovery of fabric which had been washed and dried that processes did not affected by that. Although both the parameters denote degree of wrinkle recovery of the fabric,but there are obvious differences.Moreover,wrinkle recovery angles in warp and in weft of fabrics are not higher by increasing of fabric counts in warp and in weft respectively,and the weaves influence significantly wrinkle recovery angle of fabrics.The wrinkle recovery behavior of fabrics and the action of shape memory polymers is influenced by the changes in environment such as temperature,humidity etc.Hence,a study was conducted to understand the recovery behavior fabrics in hot water and hot air environments.The shape memory fabrics which were set to flat shape were deformed to form creases and then half of them were immersed in water at different definite temperatures and the other half were exposed to hot air at temperatures and the winkle recovery angles were measured.The result shows that the external environments such as hot water and air have a profound influence on the wrinkle recovery behavior of fabrics treated with shape memory polymers.The wrinkle recovery angle of fabrics treated with shape memory polymers increases under the influence of heat and a significant increase occurs over a temperature from 50℃to 60℃in both the hot water and hot air environments with about a wrinkle recovery angle of 60°.As the temperature goes beyond 60℃,the recovery is better.This indicates the point that,the shape memory polymer helps in getting back the original shape of the fabric when its switch temperature(60℃) is triggered.In both hot water and hot air the wrinkle recovery angles of fabrics have the same tendency,but the wrinkle recovery angle of shape memory fabrics is significant higher than untreated fabrics.Over 50℃the difference between the wrinkle recovery angles of shape memory fabric and untreated fabric increase as temperature rising.In 80℃water the difference is 70°and in 70℃air that is 98°.And the wrinkle recovery in hot air need much longer time than that in hot water due to different coefficient of heat transmission. Nonlinear regression analysis was used for finding the relationship between the wrinkle recovery angle and the temperature of shape memory fabrics in hot environment.The curvilinear equation which wrinkle recovery angle vary with temperature in hot water is y = 3.4467 x0.5579,and that in hot air is y = 3.2820 x0.5910.Properties of 10 kinds cotton and cotton-type fabrics finished by shape memory polymer are discussed.Fabric winkle recovery performance indexes including wrinkle recovery angle,flat appearance and crease retention and physical properties such as dimensional stability,strain at Max.load,correlativity between tensile strength and tearing strength retention were discussed through grey correlation analyzed.The result shows that the wrinkle recovery angles of cotton and cotton-type fabrics finished were improved and the physical properties changed due to the action of shape memory chemicals.The tensile strength retention of shape memory fabrics is approximate to that of fabric finished conventional DMDHEU,while the tearing strength retention of shape memory fabrics is obvious higher than the latter.Especially the tearing strength retention of twill mostly did not decrease but increase 36%.It is possible that in the fabrics finished by shape memory polymers the interfibre and yarn friction have reduced so that fibers and yarns can move more during tearing fabrics leading to increase tearing strength retention.The result shows that the dimensional stability of shape memory fabrics is the most correlativity with winkle recovery properties such as wrinkle recovery angle in warp, wrinkle recovery angle in weft,flat appearance and crease retention, whereas the tearing retain is the least correlativity with them.For wrinkle recovery angle it is better correlativity with tensile breaking strength retention in both warp and weft than breaking elongation rate.The breaking elongation rate of cotton fabrics finished mostly decrease.The breaking elongation rate of T/C fabrics finished increase with polyester. For T38%to C62%fabric finished the breaking elongation rate is lower than that of the fabric unfinished,but for T65%to C35%fabric finished it is higher than that of the fabric unfinished.For all kinds of fabrics the tensile strength retention is very different with the retention in weft being obvious lower than that in warp and the retention of cotton fabrics being obvious lower than T/C fabrics.By means of KES the analysis reveals that the elasticity and wrinkle recovery of C1 fabric finished by shape memory chemicals are significantly improved;and geometrical roughness and resilience of compression are better;but the frictional coefficient is higher and work of compression is lower.The bending rigidity of all kinds of shape memory fabrics all decrease after washed,but the hysteresis of bending moment of fabrics are most higher after washed this is,after bended the fabrics are not easy to recover.The original elasticity of linen fabric is well known bad but its hysteresis of bending moment obviously increase with a better recovery after washed.For surface performance geometrical roughness of shape memory fabrics are almost higher after washed except for surface frictional coefficient which both increase for linen and cotton fabrics with high absorbability but it slightly decrease for T/C fabrics.For compression performance,the fabrics washed are not easy to compress and if compressed the fabrics can be not easy to recover.The Fabric Eye,which is a digital system for the objective evaluation of fabric appearance such as surface area,thickness,volume, roughness and so on,developed by the Hong Kong Polytechnic University, was used to measure and analyze fabric appearance.By means of Fabric Eye the analysis shows that the surface area,thickness,volume,roughness of two kinds of cotton fabrics all increase after finished.It was observed that the plain C2 fabric absorbed more shape memory emulsion with the thickness and volume rising 72%than the twill C1 fabric with those rising 50%.Usually for cotton fabrics the strength in warp and weft are different with strength in weft lower than that in warp.Most of greiges need the post processing such as singeing,bleach,boiling-off,dyeing,heat setting and resin finishing and so on,which can make the changes for structure and performance of fabrics.Generally,after finishing the loss of strength of fabrics in weft was higher than that in warp.It can be found that the weft strength of fabrics distinctly improved by means of the micro-stretching and stopping and the circle micro-stretching under a certain stretching rate, a certain time or circle times.After micro-stretching the fabrics were finished by shape memory polymer and then the fabrics finished were stretched up to be broken.The time of pause is closely interrelated to strength.For micro-stretching and stopping the time of pause for the most breaking strength of fabrics finished is mainly the same as that of fabrics unfinished,which under the 7%stretching rate the breaking strength is the max.in one and half of minutes for both fabrics finished and unfinished. The higher stretching rate is,the shorter times of pause for the most breaking strength is.The circle times are closely interrelated to strength. For circle micro-stretching the circle times for the most breaking strength of fabrics finished is basic the same as that of fabrics unfinished,which the circle times for the most breaking strength are 35times,20times and 15times respectively for stretching rate 3%,5%and 7%.The higher stretching rate is,the lower circle times for the most breaking strength is.
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