Study Of Shape Memory Behavior Of Rubber/hindered Phenol Hybrid Cross-linked Material

Today，Shape-Memory Polymer was one of the hotspots in the fieldof materials research. Rubber itself had shape memory effect，but its glasstransition temperature （T_g）, which was also its shape memory transitiontemperature (T_trans), was far below normal temperature. This limited theapplication of rubber in the field of shape memory polymer （SMP）. Therefor,it was necessary that raise the T_gof rubber to make rubber can be applicated inreality.The rubber/hindered phenol hybrid cross-linked materials was preparedby the method of organic hybrid and curing process at high temperature, thematrix of which was Nitrile-Butadiene Rubber （NBR）、polyacrylate rubber（ACM） or Chloroprene Rubber （CR）. The microstructure and thermal property,dynamic mechanical property, shape memory property of the materialsprepared were investigated by Scanning Electron Microscope （SEM）, X-RayDiffractometer （XRD）, Differential Scanning Calorimetry （DSC）, DynamicMechanical Analyzer （DMA） and high and low temperature materials testingmachine. Under were the main conclusions.1. NBR/AO-80hybrid cross-linked materials were successfullyprepared. The results showed that, each NBR/AO-80had just one T_g, andwhen the addition of AO-80increased from0phr to120phr, the T_gof materials raised from-12.3℃to14.7℃. The reason of this was that therewas a lager number of strong hydrogen bond between AO-80and NBR. In theother words, the T_transof NBR was raised by adding AO-80. The strain fixityrate （R_f） of NBR/AO-80was higher than97%, and the strain recovery rate （R_r）was higher than94%, and the R_fand R_rwas still steady in four shape memorycycle. The strain of shape memory test of NBR/AO-80reached400%. At thesame time, the mechanical property was reinforced by adding AO-80.2. NBR/AO-60hybrid cross-linked materials were successfullyprepared. The results showed that, each NBR/AO-60had just one T_g, andwhen the addition of AO-60increased from0phr to100phr, the T_gofmaterials raised from-21.9℃to1.3℃. The reason of this was also thatthere was a lager number of strong hydrogen bond between AO-60and NBR.In the other words, the T_transof NBR was raised by adding AO-60. The R_fofNBR/AO-60was higher than95%, and the R_rwas higher than96%, and the R_fand R_rwas still steady in four shape memory cycle. The strain of shapememory test of NBR/AO-60reached400%. At the same time, the mechanicalproperty was reinforced by adding AO-60.3. ACM/AO-80hybrid cross-linked materials were successfullyprepared. The results showed that, each ACM/AO-80had just one T_g, andwhen the addition of AO-80increased from0phr to80phr, the T_gof materialsraised from-15.3℃to12.0℃. The reason of this was that there was a lagernumber of strong hydrogen bond between AO-80and ACM. In the otherwords, the T_transof ACM was raised by adding AO-80. The R_fofACM/AO-80was higher than97%, and the R_rwas higher than98%, and theR_fand R_rwas still steady in four shape memory cycle. The maximal strain of shape memory test of ACM/AO-80rose from100%to300%by increasingof AO-80. Although the mechanical property was reinforced by adding AO-80,the the mechanical property of ACM/AO-80was still poor.4. CR/AO-80hybrid cross-linked materials were successfullyprepared. The results showed that, the compatibility of CR and AO-80waspoor, and ACM/AO-80had obvious split-phase structure. By analyzing, atemperature of40℃was suitable to be the T_transof CR/AO-80, which wasclose to the melting point （Tm） of CR crystalline region and the T_gof AO-80.AO-80had remarkable influence on the R_fand R_rof CR/AO-80, and the R_fCR/AO-80added60and80phr AO-80was higher than98%and R_rwashigher than96%. The R_fand R_rof CR/AO-80was still steady in four shapememory cycle. When the strain of shape memory test was higher than300%,the R_fof CR/AO-80was higher than it under low strain.