| Fiber-reinforced continuous composite pipe has become the development direction of oilfield process pipe to overcome high corrosion problems,convenient operation and intelligent pipeline.Its material selection,structural design,continuous production technology and its promotion and application in oil and gas fields belong to the world’s cutting-edge technologies.Based on high-density polyethylene(HDPE)lined pipes,composite pipes with glass fiber impregnated epoxy resin winding as a reinforcement layer have the advantages of low cost and easy manufacturing,and are a common structural type for spoolable continuous composite pipes.However,the low heat resistance,the fast curing rate required by the continuous production process,the heat resistance,spoolable and mechanical properties of the composite pipe are still difficult points for coordination in many aspects of the system.In this paper,according to the preparation requirements of the composite pipe with HDPE as the lining pipe and epoxy resin-glass fiber as the reinforcement layer,the epoxy-anhydride curing system was selected,and the curing kinetics and heat resistance of the epoxy resin system under restricted curing conditions are discussed.It can provide basic data and resin materials for the further development of epoxy resin-glass fiber composite pipe preparation.Aiming at the limited curing conditions,this article choosed the imidazole-catalyzed epoxy-anhydride curing system,and uses the DSC method to investigate the effects of the types and amounts of epoxy resin,acid anhydride and imidazole catalysts on curing kinetics and the glass transition temperature(T_g)of the cured product.The heat distortion temperature(HDT),tensile and flexural performance tests of 100℃constant temperature cured products were carried out,and the influence of epoxy resin types,toughening agents and additives on heat resistance and ductility was discussed.We selected E44 as the basic epoxy resin substrate,the amount of the catalyst1-cyanoethyl-2-ethyl-4-methylimidazole was 4%(wt),and the amount of the curing agent methyltetrahydrophthalic anhydride(MeTHPA)was 73%(wt)epoxy resin system with 15%(wt)of toughening agent MX154.In the meanwhile,the reversible addition-fragmentation chain transfer(RAFT)polymerization method was used to prepare acrylic acid contained acrylate copolymers.As an additive,through in-situ reaction with epoxy,a heterogeneous network of high functionality and long network chains was constructed,and investigated its effect on the heat resistance and ductility of the epoxy-anhydride curing system.The results show that a suitable copolymer structure is expected to harmonize the contradiction between heat resistance and ductility,and become a kind of extension agent.When 2.5%(wt)of acrylate copolymer EP(MA-AA21)30 was added,the extension can be appropriately increased.Finally,it was measured that the viscosity of the selected formulation was 600m Pa·s at 35℃,and it can be cured completely within 25 minutes under constant temperature curing at 100℃.The curing degree can reach more than 95%,the cured product had an elongation of 12%,reaching the required elongation for spoolable.The heat distortion temperature reached 100℃,the tensile strength was above 75MPa,and the activation energy of the curing reaction of the selected system measured by the model-free DSC method was 70 k J/mol,and basically did not change with the degree of curing,indicating that the curing process of the system was chemical kinetics control. |
PDF Full Text Request