Mechanical And Sound Insulation Performances Of Epoxy Resin/Hollow Filler Composites

The noise brought by modern science and technology has seriously affected people’s life quality and caused great harm to people’s physical and mental health,so that noise control and isolation become an urgent problems to be solved.Traditional engineering of sound insulation is generally achieved by means of high density and large thickness materials,but these materials are generally expensive and take up large space,subsequently bring a lot of inconvenience.Low cost,light weight,excellent barrier effect of high-performance acoustic materials have become the preferred solution to solve the problem in noise nuisance.Epoxy resin(EP)as thermosetting polymer have a lot of excellent performances,such as the stable processing size,easy to process molding,low volume shrinkage during its curing and excellent chemical stability,which make it possess the potential as a light-weight soundproofing material.However,poor toughness and sound insulation property of EP prevent its practice application,so that these properties are necessary to be enhanced.In this paper,four hollow functional fillers containing hollow glass ball(HGB),hollow polystyrene spheres(HPS),hollow silica nanospheres(HSN)and hollow silica nanotubes(HSNTs),were added into the epoxy resin to prepare composites.The effects of morphology and amount of hollow fillers on the mechanical,thermal stability and sound insulation properties of the composites were studied.This dissertation includes the following four aspects:Firstly,hollow glass balls(HGB)were used as filler,and end carboxyl liquid butyronitrile rubber(CTBN)as thickener and toughening agent,as well as methyl hexahydrophthalic anhydride and 2-ethyl-4-methylimidazole as curing agent and accelerator,to fill the epoxy resin.The above mixture were stirred and defoamed by using the rotationrevolution mixer,and then the EP/CTBN/HGB ternary composites were obtained through the curing process of temperature programming.The EP/CTBN/glass balls(GB)ternary composites were also prepared to carry out control experiments.The results show that the CTBN makes the fracture surfaces rough so that the composites changing from brittle fracture to ductile fracture.HGB makes up for the deterioration of the modulus although the composite modulus are reduced by the CTBN.When the CTBN content is 12 wt% and the HGB content is 30 vol%,mechanical properites of the EP/CTBN/HGB composites,containing impact,flexural and tensile strength as well as flexural modulus,are better than those of the pure EP except for the tensile modulus.The sound insulation performances of the composites are also improved by adding the CTBN and HGB,and the average sound transmission loss value(average STL)of the EP/CTBN composites are enhanced by 115% comparing with that of neat EP.The average STL of the EP/CTBN/HGB composite with 30 vol% of HGB is further improved by 30%.The EP/CTBN/HGB composites possess more excellent sound insulation performance than the EP/CTBN/GB composites under the same conditions.Secondly,with HPS as a filler,epoxy resin as the matrix and polyethylene glycol(PEG)as toughening agent,the EP/HPS and EP/PEG/HPS composites were prepared by the similar curing conditions and curing process as the EP/CTBN/HGB composites.Experiment results show that mechanical properties of the EP/HPS composites can slightly be improved by the low content of HPS while those are almost decreased when the HPS content increases.However,adding PEG can improve all mechanical properties containing impact strength,flexural and tensile properties of the EP/HPS composites.The impact and flexural as well as tensile strength of EP/PEG/HPS composites are significantly better than those of neat EP except that the modulus are slightly reduced when the PEG loading is 10 wt% and the HPS loading is 32 vol%.The addition of HPS can improve the sound insulation performances of the EP/PEG/HPS composites while the STL values of the EP/HPS composite are also increased with HPS content increasing.Moreover,EP/PEG/HPS composites display better sound insulation performances than the EP/HPS composites.The average STL value of the EP/PEG/HPS composites with 32 vol% of HPS and 3 mm thickness increases to 42.1 d B from 19.0 d B of the neat EP.The average STL values of the composites containing the same filler content and the neat EP rise to 55.7 d B and 47.1 d B when the thickess of these samples are increased to 10 mm.Thirdly,with HSN or silica nanospheres(SN)as a filler,the EP/HSN and EP/SN composites were prepared by the same curing conditions and curing process as the EP/CTBN/HGB composites,respectively.Their thermal stability,mechanical and sound insulation properties were investigated and compared.The results show that,the mechanical properties of EP/HSN composites can be improved by adding small amount of HSN,but they are decreased when the HSN content further increasing.When the HSN loading is 2.0 vol%,the flexural and tensile properties of the EP/HSN composites are better than those of neat EP except that the impact strength of EP are slightly lowered.Moreover,mechanical properties of the EP/HSN composites are better than those of the EP/SN composites and HSN and SN can improve the thermal stability of EP composites.Adding HSN or SN can also enhance the soundproofing properties of the EP matrix composites and they are further improved with the filler loading increasing.The HSN possesses more excellent ability than the SN to improve the sound insulation performance.The average STL values of the EP/HSN and EP/SN composites with 2.0 vol% of filler and 3 mm thickness increase to 44.3 d B and 33.9 d B from 17.2 d B of the neat EP,respectively.Fourthly,with HSNTs as the hollow filler,the EP/HSNTs composites were prepared by the same curing conditions and curing process as the EP/CTBN/HGB composites,and the thermal stability,mechanical and sound insulation properties of the composites were studied.The results show that the addition of small amount(1.0 wt%)of HSNTs can reinforce the mechanical properties of the EP/HSNTs composites while their mechanical properties almost show downward trend with HSNTs content increasing.Howerver,the fracture toughness and flexural strength as well as tensile strength of the EP/HSNTs composites are better than those of the neat EP even if the HSNTs loading reaches 3.0 wt%.The HSNTs could also improve the thermal stability of the EP/HSNTs composites.Adding the HSNTs could enhance the sound insulation properties of the EP/HSNTs composites and the STL values of the composites are further improved with the HSNTs content increasing.The results show that the average STL value of the EP/HSNTs composites with 3 wt% of HSNTs is increased by 150%,changing from 17.2 d B of the neat EP to 43.3 d B of the composites,when the sample thickness is 3 mm.The average STL value of the composites containing the above same HSNTs content is increased to 57.9 d B from 45.9 of the neat EP,rising by 26%,after the sample thickness reaches 10 mm.The above results indicate that adding HSNTs demonstrates more obvious effect on the sound insulation performance of EP matrix composites for thin panal products.