Preparation And Properties Of F-T Wax Modified By Maleic Anhydride

F-T wax is mainly composed of straight-chain saturated alkanes,which has the characteristics of low impurity content and strong oxidation resistance.It is widely used in candle,rubber protection,plastic processing and other fields.In recent years,F-T wax production capacity of our country has increased substantially and the market gradually tends to saturation.F-T wax enterprises can not establish a foothold only with the low-end primary products.Therefore,the development of series modified F-T wax products with high added value has become the research focus of wax industry.In this paper,maleic anhydride grafted F-T wax(FT-g-MAH)with high grafting rate was prepared by melting grafting modification method,and the application performance of FT-g-MAH as a processing lubricant for PVC was further investigated.Grafting rate and whiteness were used as important indexes to evaluate FTg-MAH.Firstly,FT-g-MAH was prepared with maleic anhydride(MAH)as graft monomer,dicumyl peroxide(DCP)and benzoyl peroxide(BPO)as initiators in a batch reaction unit.The effect of feeding method,temperature,time and other important operating conditions on grafting rate and whiteness value of FT-g-MAH was explored,and the optimal process conditions were determined.Then,FT-g-MAH was prepared under optimal technological conditions using a continuous reaction device,and the FT-g-MAH prepared by two reaction devices were compared.The results showed that the continuous reaction device was better than the batch reaction device.The optimal process conditions were as follows: DCP was the initiator,reaction temperature was 170 ℃,space-time was 20 min,stirring speed was 500 rpm,MAH was 0.14 phr,DCP was 0.10 phr.Under the optimum conditions,FT-g-MAH with grafting rate of 5.6% and whiteness of 41.0 was obtained.Compared with the indirect reaction device,the grafting rate was increased by 1.3% and whiteness by 3.2.The successful grafting of MAH onto F-T wax molecules was demonstrated by Fourier-transform-infrared-spectroscopy(FTIR).The application performance of FT-g-MAH as PVC processing lubrication was investigated.Firstly,thermo-gravimetric analysis(TGA)and differential scanning calorimetry(DSC)were used to characterize the thermal stability and melting crystallization behavior of FT-g-MAH,and the effects of grafting rate on the properties of FT-g-MAH,such as melting point,kinematic viscosity and needle penetration were investigated.The results show that the stability of FTg-MAH is better than that of F-T wax.With the increase of grafting rate,the kinematic viscosity and penetration degree of FT-g-MAH increased,and the drop melting point decreased.Compared with other modified wax lubricants,FT wax has the characteristics of low kinemical viscosity and low needle penetration.Then,the rheometer was used to investigate the lubrication properties of FT-g-MAH.The results showed that the FT-g-MAH containing polar and non-polar molecules had both internal and external lubrication,and its lubrication effect was similar to stearic acid.FT-g-MAH and calcium stearate compound,can delay plastination,so that the lubrication system external lubrication effect is enhanced;When FT-g-MAH is combined with F-T wax,it can promote plasticization and enhance the internal lubrication effect of the lubrication system.FT-g-MAH can replace stearic acid functionally.