Preparation Of Phthalocyanine Nucleating Agents And Effect On Properties Of Polypropylene

As one of the five general-purpose plastics,polypropylene is widely used in various fields of life.However,polypropylene has the disadvantages of low impact strength,sensitivity to notches,and poor toughness.Modified polypropylene has become a research hotspot.Adding a nucleating agent is one of the most convenient and effective ways to modify polypropylene.The addition of nucleating agents can effectively improve the spherulite morphology,spherulite size and spatial regularity of polypropylene,thereby enhancing the mechanical properties and thermal stability of polypropylene.Three phthalocyanine nucleating agents were prepared in this paper,tetracarboxylic phthalocyanine?TAP?,tetramethoxyphenoxyphthalocyanine?TMPP?,and tetracarboxyphenoxy-phthalocyanine?TCPP?.Combined with the molecular characteristics of aromatic carboxylic acid nucleating agents,structural modification of phthalocyanine macromolecules with excellent optical properties and thermal stability is carried out.The three nucleating agents were mixed with polypropylene to prepare modified polypropylene samples.To study the effect of the addition of TAP,TMPP and TCPP on the crystalline properties,thermal stability and mechanical properties of polypropylene,and to study the optimal addition amount of TAP,TMPP and TCPP by X-ray diffraction?XRD?,polarized light microscope?PLM?,scanning electron microscope?SEM?,differential scanning calorimetry?DSC?,thermal weight loss method?TG?and mechanical properties tests.Preparation of precursors 4-p-methoxyphenoxyphthalonitrile and 4-p-carboxyphenoxy-phthalene using 4-nitrophthalonitrile,p-hydroxybenzoic acid and p-methoxyphenol.Three phthalocyanine nucleating agents were synthesized using 4-carboxyphthalonitrile and two precursors.The structure and properties of TAP,TMPP and TCPP were characterized and analyzed by melting point determination,UV-Vis and FT-IR.The results show that the melting points of TAP,TMPP and TCPP are all greater than 200?and higher than the melting point of polypropylene,and can act on polypropylene;UV-Vis absorption spectrum analysis of TAP,TMPP and TCPP aggregation,TAP,TMPP and TCPP are not easy to aggregate,It has good compatibility in polypropylene melt.XRD,SEM and PLM test results show that the addition of the three nucleating agents all induce polypropylene crystallization to generate a large amount of?crystalline polypropyle-ne;compared with pure polypropylene,the addition of the three nucleating agents all increase the crystallization speed of polypropylene,reduce the size of spherulites,make the distribution of spherulites more uniform,the spatial regularity is higher,and the crystallization performance of polypropylene is effectively improved.The results of DSC and TG test show that the addition of the three nucleating agents can enhance the thermal stability of polypropylene,the melting peak temperature and decomposition temperature of polypropylene become larger,and the enhancement effect TCPP>TAP>TMPP.Mechanical property tests show that all three nucleating agents can enhance the impact,tensile and bending properties of polypropylene.The optimal dosage of all three nucleating agents is 0.3 wt%.TAP has the best effect on improving the impact performance.The impact strength reaches 3.58 KJ·m^-2,an increase of 10.15%.TCPP has the greatest improvement in tensile and bending properties,with tensile strength reaching 41.58 MPa,an increase of34.78%,and bending strength reaching 59.55 MPa,an increase of 29.18%.