The Design Of Functional Rubber Based On The Regulation Of T_g

As an indispensable industrial material,rubber has a wide range of sources and low price,and has a broad application prospect in many fields.However,in the practical application of rubber,its high elastic value is mainly utilized,which limits the application of rubber to some extent.Therefore,the research on other phases?such as glassy state?of rubber is of certain significance to the application of rubber.Functional materials are a hot topic in the field of materials research.Because of its many excellent properties,rubber can be used as a good functional material matrix.However,the preparation of some functional rubber is closely related to the T_gof rubber(for example,the maximum damping property of the shock-absorbing and noise-reducing rubber is near the T_gof rubber;Shape memory the shape transition temperature of rubber is generally T_gof rubber.The self-healing property of self-healing conductive rubber is closely related to the flexibility of the rubber molecular chain,which is related to the molecular structure and is generally characterized by T_g.However,the T_gof rubber is relatively low,which leads to certain challenges in the study of these functional rubbers.Based on this consideration,a T_gregulation strategy was proposed in this paper for the regulation of rubber T_gby means of filler filling,interfacial interaction and molecular chain modification.This strategy was applied to the field of shock-reduction and noise-reduction rubber and shape memory rubber respectively,and the good performance of chlorinated butyl rubber?CIIR?and carboxystyrene butadiene rubber?XSBR?shape memory material was prepared.On this basis,the application of this strategy in the field of ENR self-healing conductive materials is also explored.The research contents and results are as follows:?1?In this paper,a kind of specific damping material with high damping and wide effective damping temperature range??T?was designed by regulating glass transition temperature?T_g?.The damping material was prepared based on chlorobutyl rubber?CIIR?,which exhibits high initial damping performance but also low T_gand narrow?T.40 phr carbon black?CB?was added to promote the T_gof CIIR as well as?2?acted as the reinforcing agent.Simultaneously,different dosages of terpene resin?TR?were incorporated to further control the T_gand?T,and improve the interfacial compatibility between CIIR with CB.Consequently,the T_gand?T of the composites could be regulated by changing the amount of TR under the premise of ensuring good damping and mechanical properties.Especially,when the content of TR was 30 phr,the T_gof composite was tuned from-30?of blank sample to 0?and?T was widen from?-60?,35??to?-60?,60+??.Maximum loss factor(Tan?_max)was increased from 1.1 to 1.3 as well.In addition,this kind of damping material possessed outstanding actual shock absorption and noise reduction performances corroborated by resonance test and noise reduction test.Therefore,this damping material shows great potential in high-quality damping rubber products.?3?In this paper,dual-response shape-memory polymers?SMPs?based on carboxylic styrene butadiene rubber?XSBR?/ferriferrous oxide?Fe₃O₄?/zinc dimethacrylate?ZDMA?were designed.Fe₃O₄was incorporated to endow XSBR with a magnetic property and improve its glass transition temperature?T_g?.ZDMA was employed as an in situ reinforcer and compatibilizer for Fe₃O₄and XSBR,which further improved T_gof the SMPs by introducing ionic cross-linking points.With incorporation of 10 phr ZDMA,T_gincreased to 28.3?,the shape fixation ratio of the SMP was?100%at room temperature,the shape recovery ratio was?100%in both a thermal field and an alternating magnetic field,and the tensile strength reached 30.26MPa.The chemical and physical properties of the SMPs were characterized by curing tests,cross-link density measurements,scanning electron microscopy,differential scanning calorimetry,and tensile tests.Such dual-response SMPs exhibit potential applications in intelligent biomedical devices over a wide temperature range.?4?Based on the above ideas,we considered that the self-healing conductive rubber is closely related to the flexibility of the molecular chain,which can be reflected by T_g.So we explored its application in the field of epoxy natural rubber?ENR?self-healing conductive rubber by means of T_gregulation.In this paper,through the synthesis of 2-aminopyridine?AP?and ENR,an amino group?-NH₂?was introduced at the reactive epoxy group to obtain the graft product ENR-AP.Then,?5?hexahydrate ferric chloride?Fe Cl₃·6H₂O?was added into the ENR-AP system,and the ion coordination product with self-healing property was obtained by the coordination reaction between Fe³⁺and-NH₂.Finally,the introduction of conductive particle-carbon nanotubes?MWCNTs?with different dosage in the ENR-AP@Fe³⁺system was considered to obtain self-healing conductive rubber ENR-AP@Fe³⁺-MWCNTs.The T_gof the material was regulated by changing the dosage of MWCNTs to balance the self-healing and conductive properties of the material.In this process,the effects of reaction time?4h?8h?12h?on grafting efficiency were studied by infrared and nuclear magnetic resonance tests?NMR?.Based on grafting reaction of 12 h?a fixed the grafting rate of 43.59%?,and studied the dosage of Fe³⁺?theoretical saturation is 25%,50%,75%,100%?on the properties of the coordination reaction and self-healing effect was studied,ultraviolet spectroscopic characterization results appeared at 360 nm coordination bond absorption peak,tensile properties test showed that adding 75%Fe³⁺condition has the optimum self-healing properties with repair rate of close to 80%.Under the condition that the Fe³⁺dosage was 75%of the theoretical saturation state,5phr CNT were added,and the conductivity of the material was studied by four-probe test and conductive loop test.The results showed that the material had a conductive effect,and the conductivity was about 5×10^-2s/m.