Modify Fluorocarbon Elastomer By Blending Technology

Fluorocarbonelastomer (FKM) exhibit high thermal, chemical, ageing and oilresistance, meanwhile they are hard to process, besides, fluoroelastomers displayinferior low temperature elastomeric properties and they are very expensivecustomarily. So it is very important to modify FKM in order to improve it'sproperties, match new market needs, reduce the cost. Blending of polymers is awell-established technology, and many mixing techniques are available today.This thesis uses Polyvinylidene Fluoride(PVDF) blending with two type ofFKM in order to enhance the mechanical properties and resistance to polarsolvents of FKM, discussing the effect of PVDF on morphology and mechanicalProperties of FKM. Results of theological testing indicates that equilibrium torqueof FKM/PVDF blending decreases after adding PVDF into FKM; apparent viscosityof FKM/PVDF blending decreases when shear rate increase, but it does not changeobviously when the content of PVDF increases; Mooney of FKM/PVDF blendingincreases extremely. The results of vulcanization shows that the addition of PVDFresulted in delay of T₁₀ and T₉₀, which means the decreasing of vulcanizationvelocity, M_L and M_H. Scanning electron microscopy (SEM) results showed thatFKM/PVDF blending is made of a continuous phase of FKM and a dispersed phaseof PVDF, the average particle size of dispersed phase less than 1μm, and the PVDFtrends to form a continuous phase when it's content increase. The incorporation ofPVDF into FKM resulted in great increase of tensile strength, tearing strength, hardness and compression permanent deformation of FKM/PVDF blending butdecrease in elongation at break. Dynamic mechanical analysis (DMA) results showthat when the content of PVDF increases, the storage modulus of the FKM/PVDFblends increases above the the glass transition temperature (Tg) of FKM, whereasdecreases below the Tg of the FKM; Tg of FKM does not shift obviously, it appearsat 2.7℃around, Tg of PVDF does not appears but it does when it's content up to20%. PVDF makes the enhancement in polar solvent resistance of the FKM.Poly(ε-caprolactone)(PCL)/FKM blending were also studied in the thesis, inorder to improve the fluidity of FKM. The effect of PCL on morphology andmechanical properties of FKM were discussed. The results of rheological testingindicates that equilibrium torque of FKM/PCL blending decreases extremely afteradding PCL into FKM; apparent viscosity of FKM/PCL blending decreases whenshear rate increase, and it decreases obviously when the content of PCL increases;Mooney of FKM/PCL blending decreases extremely. Studying the vulcanizationshows that the addition of PCL resulted in shorten of T₁₀ and T₉₀, increasing ofvulcanization velocity, decrease of M_L and M_H. SEM results show that FKM/PCLblending is made of two continuous phase of FKM and PCL, and the PCL trendsto coalescence when it's content increase, the diffusion of FKM and PCL formstransition layers and they distributes in the elastomerie matrix uniformly. Theincorporation of PCL into FKM resulted in great increase of hardness andcompression permanent deformation of FKM/PCL blending but decrease in tensilestrength and elongation at break. DMA results show that when the content of PCLincreases, the storage modulus of the FKM/PCL blends increases above the the glasstransition temperature (Tg) of FKM, whereas decreases below the Tg of the FKM;Tg of FKM does not shift obviously, it appears at 2.7℃around,Tg of PCL does notappears.