Effect Of Nucleating Agents On Property Poly Biodegradable(3-hydroxybutyrate-co-4-hydroxybutyrate)foam

The development trend of plastic products is how to ease the pressure on the environment.Polyhydroxyalkanoates?PHA?is a new kind of biodegradable polymer materials,with physical and chemical properties similar to that of the polymer plastic,and the gas PHA apart,biocompatibility,nonlinear optics,biodegradable,piezoelectric,and many other excellent performance is high polymer plastic do not have.So the PHA have become the focus in the modern plastic products.Poly?3-hydroxybutyrate-co-4-hydroxybutyrate?is the fourth generation product of PHA.Compared with other PHA products,the introduction of the copolymer unit 4HB not only improved the material toughness and impact strength,the price is more lower,but still higher than other traditional petroleum-based plastic materials.So this thesis study on the P34HB foaming material,in order to achieve lightweight to reduce the volume price,at the same time achieve the purpose of reduce the thermal conductivity,strengthen the buffer performance,enhance the ability barrier voice.P34HB has many shortcomings on process and performance,such as:?1?the poor thermal stability,easy hydrolysis;?2?the processing temperature range is relatively narrow,the processing molding is difficult too;?3?the crystallization velocity is too slow that makes the processing molding cycle is too long;?4?low melt strength.In order to solve the shortcomings of P34HB which exists in the processing and performance,this paper adopts P34HB as matrix resin,use the method of chemical modification and physical modification,to join bubble blast-holes nuclear agent,cross-linking agent in material,and then prepared foaming P34HB material by moulded chemical method.In this paper the optimum process conditions of preparing P34HB foaming materials was determined by means of mechanics performance test as follows: First,the various raw materials dry after 24 h of high-speed blending machine mixing;Second,put them into the double roller to melt blending,mixing machine mixing temperature of 90¹00?,the mixing time is 5¹0 minutes,and get the plastication piece;What's more,use the moulding foaming plate vulcanizing machine,at the temperature of 150?,and pressure to 10 MPa,keep 6 minutes;Finally received the P34HB foam sheet.Through SEM and Image analysis software?Image Pro-Plus 6.0?respectively to observe the foaming material of bubble pore shape and pore diameter distribution,the bubble got the bubble pore size uniform distributed evenly and porpus materials.By TGA on the material's thermal properties are analyzed,and found that the cross-linking agent can effectively improve the thermal stability of materials.By XRD the crystallization properties of foam material was analyzed,and found that the addition of nucleating agent can effectively improve the crystallinity of the materials.In this thesis,the selection of the foaming agent is sodium bicarbonate?NaHCO₃?or azodicarbonamide?AC?+ zinc oxide?ZnO?compound foaming agent.Study found that:?1?With the sodium bicarbonate?NaHCO₃?as foaming agent when the content of DCP was 1%,the foaming effect get best,the bubble hole density of the material is 27.87 / mm³ and the average diameter is 247.84 microns.?2?With the AC+ZnO as the foaming agent when the content of DCP was 2%,the foaming effect get best,the bubble hole density of the material is 83.86 / mm³ and the average diameter is 172.03 microns.This thesis chooses the nucleating agent respectively boron nitride?BN?,lignin or calcium carbonate?CaCO₃?.The study found that:?1?With the boron nitride?BN?as the nucleating agent,when the content of BN is 1%,the foaming effect get best,the bubble hole density of the material is 61.02 / mm³ and the average diameter is 190.88 microns.?2?With the lignin as the nucleating agent,when the content of lignin is 1%,the foaming effect get best,the bubble hole density of the material is44.03 / mm³ and the average diameter is 212.82 microns.?3?With the Calcium carbonate?CaCO₃?as the nucleating agent,when the content of CaCO₃ is 5%,the foaming effect get best,the bubble hole density of the material is 189.48/mm³ and the average diameter is 130.84 microns.