Phase Change Mechanism Of Waterborne Polyurethane Energy Storage Material And Thermo-Regulated Viscose Fiber

With more and more people preferring to buy functional textiles, developingfunctional/intelligent fabrics, increasing technological content of textiles or improving thefunctionality of clothing has become a major trend in textile industry as well as animportant condition for textile companies to occupy dominant position in domestic andforeign markets. In this dissertation, the author first designed and prepared waterbornepolyurethane phase change material (WPUPCM); moreover, utilizing spinning blendingmethod and wet spinning process, waterborne polyurethane thermo-regulated viscose fiber(WTRVF) was prepared by adding WPUPCM to viscose. Meanwhile, PEG/SiO2PCMwas prepared by adopting sol-gel technique, then PEG/SiO2thermo-regulated viscosefiber (PEG/SiO2TRVF) was prepared by employing after-treating method. Finally,WTRVF and PEG/SiO2TRVF, prepared respectively by directly fiber forming methodand after-treating method, were compared.In the first place, taking MDI, HDI, PEG, chain extenders (DMPA、BDO、EDA),catalyst (DBTDL) and neutralizer (TEA) as the raw materials, a series of emulsions, filmsand blocks about M-WPUPCM and H-WPUPCM were prepared. Moreover, the bestsolution to preparing emulsions has been determined by utilizing orthogonal experimentalmethod and taking emulsion particle size as evaluation index. FTIR result indicated thatthe experiment has successfully synthesized M-WPUPCM and H-WPUPCM. Thermalperformance test showed that WPUPCM, the phase transition of which is reversible, is athermo-regulated material with excellent thermal cycling stability. Microstructure analysisrevealed that the surface roughness of WPUPCM film improved with the increase ofemulsion particle size. POM test indicated that PUPCM still exists in crystalline state atroom temperature, but the crystal size is smaller than that of PEG; essentially, the phasetransition process of WPUPCM is the alternating process between amorphous state andcrystalline state. According to TG-FTIR test, the main product of PUPCM thermaldecomposition was CO2. By applying wet spinning method to small production line in industry and usingM-WPUPCM emulsion, H-WPUPCM emulsion and viscose fiber dope as raw materials,the author prepared M-WTRVF and H-WTRVF. Microstructure analysis revealed thatWPUPCM could well combine with VF and no obvious interface appeared, andH-WTRVF displayed more regular section than M-WTRVF. FTIR test indicated that nochemical reaction occurred between WPUPCM and VF. And thermal performance testdemonstrated that the phase transition enthalpy of WTRVF increased with the raise ofWPUPCM content, and the melting enthalpy of M-WTRVF was lower than that ofH-WTRVF; in addition, WTRVF, with reversible phase transition, possesses great thermalcycling stability. Therefore, WTRVF can be industrialized, and its’ thermal performance isapparently superior to existing commercial products, thus possessing high applicationvalue. Washing performance test showed that WTRVF displays excellent washingperformance. And according to Limiting Oxygen Index (LOI) test, the addition ofWPUPCM did not increase fire hazard of VF products. TG-FTIR test indicated that, afterhigh temperature combustion, WTRVF products were mainly H2O and CO2and no toxicor harmful gases appeared. Meanwhile, WTRVF mechanical property declined slightlythan that of VF, being similar to microcapsule RVF in the aspect of reducing magnitude,whereas, the phase transition enthalpy of WTRVF was visibly higher than that ofmicrocapsule RVF; the addition of WPUPCM decreased the frictional resistance,improved the moisture regain and the handle as well as softness and smoothness of fiber;moreover, VF bulkiness was also slightly improved due to the addition of WPUPCM.With the increase of WPUPCM content, the heating (cooling) rate of WTRVF reduced,and time for maintaining a slow heating (cooling) extended, namely,temperature-adjustable effect improved; the maximum temperature difference betweenWTRVF and ordinary VF was7℃as heating reached600s, and it was6.5℃as coolingreached600s.Furthermore, PEG/SiO2PCM was prepared by employing sol-gel technique. And thenetwork structure of SiO2has effectively wrapped PCM, thereby solving the liquid leakageproblem in the process of solid-liquid phase change. PEG/SiO2TRVF, which was further prepared, has excellent temperature-adjustable effect. The fabric handle is slightly worsethan after-treating for many tiny particles appeared on fiber surface. Thetemperature-adjustable ability improves with the increase of PEG/SiO2PCM content; themaximum temperature difference between PEG/SiO2TRVF and ordinary VF was8.2℃as the heating reached600s, while it was6.2℃as the cooling was600s. Thetemperature-adjustable fabric had a large phase change enthalpy despite the great effect ofwashing on the thermal performance of it. In summary, compared with PEG/SiO2TRVF,WTRVF has obvious advantages in the aspect of wearing property and washingperformance.