Surface Modification Of Nano-CaCO₃ And Effects On Properties Of HDPE

Polyethylene as the world's largest, with wide variety of productions is one of the most important synthetic resin, its application already goes deep into people's daily life. Although it has many advantages, but there is also some of the weaknesses properties which limited its application market.This topic use nano CaCO₃ filling modification to modify high density polyethylene to improve its mechanical properties .First coupling agent has been chose to solve the problem of reunited and poor matrix combination. Study has been taken on the modification experiments by surface processed nano-silica/nano CaCO₃ dual cooperative modified HDPE performance. Then research has been done from the Angle of nanometer calcium carbonate, using in situ polymerization of styrene modification, and the nano CaCO₃ composite particle from the reaction with HDPE reacted to the HDPE sexual blend properties. In view of the above questions made the following conclusions:(1)The surface morphology and dispersing condition of nano CaCO₃ are analyzed and compared by the analysis of FT-IR, SEM, XRD and TG.Results show that , compared with silane coupling agent KH 151 and KH570, titanate coupling agent KH101 modified the best effect. And we find optimum conditions of titanium coupling agent modification: nano CaCO₃ content 3wt%, the content of cyclohexanone is five times of nano CaCO₃, the reaction temperature is q 80℃, stirring time is 60min.(2)Use nano CaCO₃ and nano-silica separately to modify HDPE:â‘ nano CaCO₃: For filling quantity 20% 25% impact strength has maximum, content in 10%-20% tensile strength have maximum.â‘¡nano-silica: For filling quantity between 6% to 8% tensile and impact strength have maximum(3)Binary filling modification, the mass ratio of the system is Nano CaCO₃: nano SiO₂: HDPE =25:7:100,compared with HDPE separately filled with nano CaCO₃ or nano SiO₂, its impact strength and tensile has improved and not drop many from the maximum, the performance is good.(4)In situ polymerization of styrene modification of nano CaCO₃ get PS - nano CaCO₃ composite particle, choose acrylic for nano CaCO₃ surface pretreatment, through the contrast experiments obtain the best reaction conditions: the reaction time is eight hours, the content of initiator of potassium peroxydisulfate is 1% of the monomer, emulsifier dodecylbenzenesulfonic acid sodium consumption is 3% of the monomer, the dosage of modified nano CaCO₃ is 25% of monomer quantity.(5)It is indicated that in reactive blend of PS- nanoCaCO₃ and HDPE, the addition of DCP and TMPTA can improve the compatibility. Tried to add different proportions of TMPTA in blend system , results show that with the increased of TMPTA, blending systems compatibility improved, but changes from 1.0% to 2.0% is not very obvious, in this experiment the additives is 1.0%(6)Compare the compatibility and mechanical property of the blend wit different proportion of raw material, Contrast of the products, and the compatibility of the mechanical properties of the product research, when the dosage of PS - nanoCaCO₃ is 10 percent, blending modified effects is best, balance torque get maximum and has the best mechanical properties. tensile strength increased 14.2% and the impact strength increased 15.2 percent. Mechanics intensity of 80/20 reaction system is also been improved, with improvement of PS-nanoCaCO₃ the mechanical property continue decline.