Study On The Thermal Stability And Compoundation Of 3-amino-1,2,4-triazole And Its Complexes On Poly(Vinyl Chloride)

Poly(vinyl chloride)(PVC)is one of the five most important plastics in the world.It has a wide range of applications due to its abrasion resistance,electrical insulation,corrosion resistance and flame resistance,so it has a very wide range of applications in daily life.In spite of its enormous desirable characteristics,thermal stabilizers are necessary during its processing because PVC suffers from poor thermal stability resulted from inherent structural defects.Although thousands of thermal stabilizers were commercial aviliable at present,only a few of them could be used in transparent PVC products.In addition,most of the thermal stabilizers could not fulfill the actual production requirements when being used alone,which need to compound with other stabilizers.Therefore,this paper developed a new type of organic high-efficiency PVC thermal stabilizers to solve the problems of complex synthesis methods and poor thermal stability effect of existing thermal stabilizers.At frist,3-amino-1,2,4-triazole with high nitrogen content was selected as PVC thermal stabilizer,and the static thermal stability of 3-amino-1,2,4-triazole was studied by Congo red test and discoloration test.At the same time,the influence of 3-amino-1,2,4-triazole on the transparency of PVC products was studied by light transmittance/haze tester.The results showed that 3-amino-1,2,4-triazole could effectively absorb HCl and replaced unstable chlorine atoms in PVC processing,and its thermal stability could further improve when compounded with Zn St2 and epoxy soybean oil(ESBO).In addition,PVC products stabilized by 3-amino-1,2,4-triazole had a good capability for antibacterial activity,thus expanding the application scope of PVC products.Secondly,a new triazole-based zinc-containing complex(abbreviated as [Zn(ttr)(OAc)])was prepared by using the strong coordination ability between 3-amino-1,2,4-triazole and metal compounds.The static thermal stability of [Zn(ttr)(OAc)] was characterized by Congo red test and discoloration test.It could be seen from Congo red test that [Zn(ttr)(OAc)] had a strong ability to absorb HCl.Its thermal stabilization time could reach 64.1 min,which was 9 times more than that of Zn St2.Next,Zn St2 and Ca St2 were compounded with [Zn(ttr)(OAc)] to further improve the thermal stability.The results showed that [Zn(ttr)(OAc)] and Zn St2 had good synergistic thermal stabilization effect,which were consistent with the data measured by torque rheometer.This meant that [Zn(ttr)(OAc)] was a long-acting heat stabilizer with strong ability to absorb HCl,but the ability to replace unstable chlorine atoms was poor,so it had a good synergistic thermal stability effect with Zn St2.At last,in order to enhance the thermal stability of 3-amino-1,2,4-triazole and [Zn(ttr)(OAc)],in this paper,dibenzoylmethane(DBM),pentaerythritol(Pe)and epoxy soybean oil(ESBO)were compound with 3-amino-1,2,4-triazole and [Zn(ttr)(OAc)],which prepared a kind of organic composite thermal stabilizers.Because [Zn(ttr)(OAc)]/Zn St2 and DBM had the best synergistic thermal stabilization effect,a commercial Calcium-Zinc thermal stabilizer(1086F)was selected to compare with [Zn(ttr)(OAc)]/Zn St2/DBM.The results revealed that [Zn(ttr)(OAc)]/ Zn St2/DBM(1.6/0.4/0.6)could maintain good long-term thermal stability of PVC during processing and a shorter plasticizing time than 1086 F,which indicated that the composite thermal stabilizer in this paper had great application value in the actual processing of PVC.