Structure Design And Application Of Fischer-Tropsch Wax/Attapulgite Coefficent Polymer Additive

Fischer-tropsch wax(FTW)has a long carbon chain structure similar to that of lignite wax.It is considered that the application of functional lignite wax and the derivatives of lignite wax as polymer auxilliers.Theoretically,functional FTW and the derivatives of FTW have potential in the field of polymer additives.Attapulgite(ATP)comes from a wide range of sources and can be used as flame retardant and nucleating agent for polymers.However,The application of ATP in polymers due to the poor interinterface compatibility between ATP and non-polar polymers.In this theses,the Fischer-Tropsch wax/attapulgite co-effecting polymer functionalization agent(FATP)was prepared by molecular structure design,which theoretically has the functions of lattice matching,flame retardant,nucleation and lubrication.According to the theoretical function of FATP,isotactic polybutene-1(i PB),polyadipate-butylene terephthalate(PBAT)and recovered polypropylene(RPP)were selected to explore the mechanism of FATP in the polymers.(1)Fischer-tropsch acid(MAFT)was prepared by grafting maleic anhydride.The maximum MAFT acid value(50 mg KOH/g)was obtained under the following conditions: reaction time was 5 h,reaction temperature was120 ℃,MAH dosage was 0.6 g,DCP dosage was 0.02 g.Then,the FATP was prepared by esterification reaction.The maximum esterification rate(58.32%)of FATP was prepared under the following conditions: reaction time was 6 h,reaction temperature was 120 ℃,addition amount of the p-aminobenzene sulfonic acid was 0.3 g,the MAFT was 5 g and the ATP was 1 g.FTIR,water contact Angle test,XRD analysis and the scanning electron microscopy proved the successful synthesis of MAFT and FATP,while the lattice parameters of ATP did not change.(2)The different contents of FATP was introduce into the i PB by the melt blending method and the crystal transformation behavior of composites was explored.The results show that the addition of FATP improves the bending strength of i PB/FATP composites and the bending strength of i PB+5%FATP composites annealed for only one day is much higher than that of i PB composites annealed for seven days.In order to further explore the mechanism of FATP promoting i PB crystal transformation behavior,differential scanning calorimeter was used to study the crystallization behavior of the composite during nucleation and growth stage.The results show that the form I content of i PB+5%FATP composite is the highest at the nucleation stage,and the content of i PB+5%MAFT composite is similar to that of pure i PB,which indicates that the lattice matching and interface compatibility synergically promote the generation of form I of i PB.At the growth stage,the form I content of i PB+5%FATP composite is the highest and the form I content of i PB+5%MAFT is higher than that of i PB and i PB+5%ATP,indicating that lattice matching and internal lubrication play a major role in the growth stage of form I of i PB.(3)Different contents of FATP were introduced into PBAT by melt blending method and the flame retardant performance of composites was studied.The SEM results showed that the interface compatibility between ATP and PBAT was obviously improved after modification.The results of oxygen index test,vertical combustion test and cone calorimeter test showed that compared with pure PBAT,the PHRR and THR values of PBAT+10%FATP decreased by27.7% and 28.3%,respectively,which indicated that the flame retardant performance of PBAT+10%FATP composite was significantly improved.In order to further explore the flame retardant mechanism,thermogravimetric infrared was used to study the flame retardant mechanism of composites in vapor phase,and scanning electron microscopy and Raman spectroscopy were used to study the flame retardant mechanism of composites in condensed phase.The results show that in the gas phase,the free water in ATP is decomposed by heat,diluting the combustible gas concentration around the composite material.At the same time,the resulting gaseous product expands the mixture of carbonaceous residue to form an expansive carbon layer.In the condensed phase,flame retardant elements such as magnesium and aluminum in FATP catalyze the matrix into carbon,forming a dense continuous carbon layer,which effectively hinders the transfer of heat and energy and improves the flame retardant performance of PBAT composites.(4)Different contents of FATP were added to RPP by melt blending method,and the crystallization and mechanical properties of composites were studied.The crystallization behavior of the composites showed that both ATP and FATP could accelerate the crystallization rate of RPP,and FATP had a more significant effect on the crystallization of RPP.The kinetics of isothermal crystallization and non-isothermal crystallization showed that the addition of FATP increased the crystallization rate of RPP.The mechanical test results showed that the mechanical properties of the composite with ATP and FATP were improved to some extent.Compared with pure RPP,the addition of FATP can increase the tensile strength,tensile modulus,bending strength,bending modulus and impact strength of RPP/FATP composites by 13.09%,11.46%,17.56%,35.7% and99.5%,respectively,basically reaching the mechanical properties of the new material PP corresponding to RPP.It can be concluded that the mechanism of FATP promoting RPP crystallization is that ATP in FATP is uniformly dispersed in RPP matrix,which plays the role of heterogeneous nucleation.Meanwhile,MAFT lubrication in FATP promotes RPP molecular chain rearrangement and compact stacking,which improves the crystallization property of RPP.