Study On Acoustic Properties Of Nitrile Rubber-based Composite Materials

This paper is mainly about the acoustic properties of some nitrile rubber-based composite materials,such as nitrile rubber foam materials,glass fiber-reinforced nitrile rubber composite materials, PPTA-reinforced nitrile rubber composite materials,and PPTA-reinforced nitrile rubber foam composite materials.And some experimental factors are discussed,in which,vesicant density,fiber content,foaming temperature and foaming time play important roles. Being different from other kinds of acoustic materials,the ones which are studied here have good anti-climate and environmental protecting properties,besides the perfect acoustic properties.When we do some researchs about nitrile rubber foam materials, we found vesicant density,foaming temperature and foaming time affect sound absorption coefficient and sound insulation remarkablely. As studying for fiber-reinforced nitrile rubber composite materials,we found that PPTA is a kind of excellent reinforced materials than glass fiber.It is a kind of effective and environmental material compared to glass fiber.On the basis of above experiments and the conclusions,we make PPTA reinforced NBR foam composite materials to enhance the acoustic properties further.Orthogonal experiment methods are used to explore the affections of some parameters to the final properties of the PPTA reinforced nitrile rubber foam materials.We also vary the thickness of the materials to enhance the acoustic properties of the composite materials further.The final experiment conditions are determined.Vesicant density at 2.5 percent,PPTA content 6%, foaming temperature 160℃,foaming time 8min,weight 76g, thickness 8mm are better conditions.And satisfactory acoustic performances are got in this condition.The average sound absorption coefficient is 0.55,and the average sound insulation 38.43dB.In the course of the experiments we found that the foaming of vesicant ADC5# and the addition of PPTA to the materials all play important roles to enhance the acoustic properties,however,they have an interactive affection.We need to added more vesicant ADC5# or enhance the foaming temperature partly,and reduce the content of PPTA are also necessary,then we can get better acoustic properties.It is mainly because that the addition of PPTA plays a negative role in the foaming process of vesicant.So we need to consider the affection of parameters'variation to the final properties of the composite materials seriously,choose reasonable experiment conditions and parameters in the course of experiment,in order to get better acoustic properties.