Co-polymerized Polypropylene Molded Flame Retardant Microcellular Foams And Its Performance Study

The foamed material obtained by microporous foaming of polypropylene(PP)has the advantages of low density,ultra-lightness,impact resistance,excellent heat and sound insulation,recyclability and has excellent prospects for development in the market and application.PP foam has gradually replaced traditional foam materials such as EPS and EPE and is used in many applications such as food service,automotive,rail transport,sports protection,medical and construction.However,the low melt strength and small modulus of polypropylene materials,the narrow temperature window for foam forming and the high requirements for foam equipment.PP is also a flammable material and poses a safety hazard in use.In this paper,copolymerized polypropylene(CPP)was selected as the object of study.In this thesis,CPP was physically blended and modified with flame retardants to produce a high performance foam with flame retardant foam by moulding physical foaming.The main research contents and results are as follows:1.CPP was chosen as the raw material and carbon dioxide fluid was used as the physical foaming agent to study the effects of different foaming conditions on the expansion rate,pore morphology and crystallinity of the foamed material.The results show that the choice of CPP as a foaming material can effectively widen the processing temperature window and shorten the moulding cycle.The CPP foaming temperature window can reach 14 ℃,the maximum expansion ratio can reach 15 times,and the cell size can be maintained at 16-250 μm.This foaming material not only has ultra light performance,but also has good thermal stability.It has good thermal temperature resistance when the temperature is lower than 130 ℃.2.The CPP/DA composite foam is prepared by adding a brominated flame retardant(DA,decabromodiphenyl ethane and antimony trioxide in a 4:1 mass ratio)to CPP and using a moulding foaming process.CPP/DA foams have excellent functional properties and appropriate DA(5%-10%wt)can have a heterogeneous nucleation effect,increasing the nucleation sites and increasing the foaming multiplicity.With 30 parts of DA,the foam is at the same time ultra-light and non-flammable.3.Introducing an environmentally friendly halogen-free flame retardant(HIFR)into CPP,CPP/HIFR flame retardant foam was prepared by moulding foaming method,and the effect of the amount of flame retardant added on the foaming behaviour and flame retardant properties of CPP materials was studied.When HIFR is added up to40%,the carbon residue of the composite foaming material is at 21.3% and the limiting oxygen index(LOI)is able to reach 31.3%.after the HIFR addition content exceeds20%,HIFR will appear agglomerated in the CPP due to non-uniform dispersion,which will adversely affect the foaming behaviour and mechanical properties of the CPP/HIFR composite.