Preparation And Characterization Of The Permanent Antistatic Agent-Poly (Ether-Block-Amide)

Plastics are widely used in many areas, such as electrical appliances, transportation, construction, electronic and electrical and information technology. However, because of the excellent electrical insulating property, the static charge will build up easily, which limits the application of plastics. Adding antistatic agents is the simplest and effective method to improve the antistatic performance of plastics. More recently, polymeric permanent antistatic agents have received great attention since they are advantageous over small molecular antistatic agents in terms of good compatibility with polymeric matrix, stable and durable antistatic performance, and no contaminant.In this thesis, we studied the synthetic process, the relationships between micro-structure and performance of poly(ether-block-amide)(PEBA). Also, PEBA was evaluated as permanent antistatic agent for ABS resin. The following conclusions are drawn:(1) A two-step process was developed to synthesize PEBA from caprolactam, diacid A and polyether B(PE-B). Firstly, polyamide 6(PA6) with two carboxyl terminal groups and designed molecular weights was synthesized at 250℃ for two hours. PA6 and PE-B are not compatible, it is very important to select a proper caping agent for PA6. PA6 capped with diacid A was found to be much more reactive than that capped with adipic acid. Then, PA6 reacted with polyether to form PEBA via esterization. Esterization condensation reaction was first carried out at 260℃ with 1 wt% (based on PE-B) catalyst C for 3hours and was futher carried on under resuced pressure about 500～1000Pa for 4hours. The intrinsic viscosity of product could reach 1.27dL/g and the fraction of extraction residue by boiling water could be low down to 1%.(2) IR and 1H-NMR spectra of the product showed that a new ester linkage appeared. It was indicated that the product should be a block copolymer linked by ester linkage. Differential Scanning Calorimetry (DSC) showed that the degree of phase separation between hard and soft segment was increased with the increase in PE-B composition. Thermal Gravity Analysis(TGA) showed that PEBA had good thermal stability in the range of processing temperature of common resins3. when Mn of PE-B was 1000g/mol and composition of PE-B was 50wt%, the surface resistivity was lowest to 4.75×109Ω. With the increase in PE-B composition and the decrease in molecular wright of PE-B, the tensile strength decreased while the elongation at break increased.(3) The properties of ABS/PEBA (molecular weight of PE-B:1000g/mol, polyether B composition 50wt%, intrinsic viscosity 1.27dL/g) blend were studied. The surface resistivity of the blend could be decreased to 1012Ω when the antistatic dosage was beyond 15wt%. And the antistatic performance was hardly influenced by the wash-washing and relative humidity, but the mechanical property decreased. When adding little SDBS or KC1 into PEBA, the antistatic performance of PEBA could be further increased.The ladder distribution of PEBA in ABS was observed by scanning electron microscopy(SEM).