Study On The Effect Of Lamellar Fillers On The Viscoelastic Behavior And Damping Properties Of Chlorobutyl Rubber

Because of its unique viscoelasticity in glass transition region,polymer materials could transfer mechanical energy into intrinsic energy for dissipation.They have been widely used for controlling vibration and noise as damping materials.Damping performance is closely related into viscoelastic behaviors and molecular motions.Due to its low coupling factor and effective chain packing,different relaxation modes(local segments motion and Rouse modes)in glass transition region of chlorinated butyl rubber(CIIR)could diverge obviously,forming pretty wide glass transition region in temperature scale.As a result,CIIR has become a hot topic in polymer damping materials field.For improving the performance of materials(mechanical properties,anti-oxidative properties,etc.),modification measures are usually required.Filling modifications are one of the most important modification measures.Different fillers have disparate effects on the different relaxation motions in glass transition region of polymer materials,resulting in diverse viscoelastic behaviors and damping performance.Two-dimensional layered fillers have gained lots of attentions in polymer composites field,especially for graphene oxide(GO).Comparing with spherical and rod fillers,layered fillers have high specific surface area which is conducive to modification process and providing more interaction sites,so they are suitable for studying the effects of interaction on composites.Layered structure endows these fillers more modification forms,so layered fillers have been widely studied and used.In order to study the influence of the interaction between fillers and matrixes on the glass transition region of CIIR,some layered fillers(GO,mGO,graphite,molybdenum disulfide,montmorillonite,mica,hydrotalcite)are mixed with CIIR through mechanical blending and solution blending.The effects of different interaction between fillers and CIIR on the different relaxation modes,viscoelastic behaviors and damping performance have been studied by DMA,which could provide guidance for choosing fillers in preparing polymer damping composites.Five CIIR/layered fillers composites have been prepared by mechanical blending.The effect of fillers loading and the interaction between fillers and matrixes on the viscoelastic behaviors been systematically discussed.The results of SEM and XRD show that five fillers could disperse uniformly in CIIR when fillers is at low content while fillers show severe aggregation when fillers is at high content,and no intercalation structure of layered fillers in CIIR is found.However,the aggregation of different fillers shows different morphology.When fillers have strong interaction with CIIR,the molecular motion would be restricted seriously.The Rouse segments show more restriction effect than the local segments.When the interaction is stronger,the merge trend of the different relaxation modes present more obvious.The slope of fitting curves of ?Tg vs.fillers content is negative.When the interaction is stronger,the height of the maximum would reduce more obviously and the damping performance would be more easily restricted.CIIR/GO nanocomposites are prepared through mechanical blending.Because of the ?-?interaction between benzene ring and GO,hindered phenol 1076(AO1076)has been used to modify the surface of GO,and mGO(GO/AO1076)is obtained.The dispersion state of GO in CIIR has been improved.The interaction between mGO and CIIR is stronger than that between GO and CIIR.The mGO could enhance the storage modulus of CIIR,and with the content increasing,the storage modulus gradually increased.Due to the physical crosslink points between mGO and CIIR,the molecular motions are restricted and the damping area decreased.Because of the strong interaction between mGO and CIIR,the two relaxation modes tend to merge with each other,resulting the narrowing of the peak width.The narrowing extent of Rouse modes peak is more severe than that of the local segment motions,implying that Rouse segments are more sensitive to the local environment than the local segments.CIIR/GO nanocomposites have been prepared by solution blending,some CIIR molecules are intercalated into the gallery of GO and some are absorbed onto the surface,forming the bound rubber.With increasing the content of GO,the storage modulus are gradually increased.The viscoelastic behaviors in glass transition region of CIIR have been distinctly changed.On one hand,GO has increased the coupling effect in CIIR molecules,on the other hand,physical crosslink points have formed between GO and CIIR molecules.As a result,the shoulder(the local segments motion)and the maximum(Rouse modes)merged into a single peak in temperature scale.Since the molecules are intercalated into GO gallery,the laminate of GO gains more slippage mobility.Due to this phenomenon,the segments between two physical points acquired more mobility,resulting in the tan? curves move towards low temperature about 20K.