Hyperbranched polyester applications in coating industry.
(1) Epoxy resin curing agent.
Hyperbranched polyester has a large number of active end groups, amino groups and carboxyl groups can react with epoxy groups.
Hyperbranched polymer with amino groups,carboxyl groups,such as PAMAM and modified hyperbranched polyester.
Carboxyl-terminated dendrimer as curing agent by reaction of a carboxyl group with an epoxy group of the epoxy fixed on the three-dimensional network structure, along with appropriate increase of the mass fraction resulting cured crosslink density increases, by the action of stretched force, the three-dimensional network structure of the epoxy resin can maintain its rigidity, can withstand greater tensile force, making the tensile strength increases. As shown, the tensile properties test due to GB/T-2568-1995, temperature (23±2) ℃, rate of extension 2mm/min, when add modified hyperbranched polyester CYD-220T mass fraction of 15 %, the tensile strength reaches the maximum 64.86 MPa, is 3 times than the system without adding it.
Using dendrimers with amino terminal group as the epoxy resin curing agent, adding the theoretical amount and without diluent, at 20 ℃, usage time and gel time of such coatings are 6.0 and 2.4 times than ethylenediamine/epoxy System. And curing at 95 ℃, 120 ℃, 150 ℃, curing speed are 1.8 times, 3.4 times and 4.8 times than ethylenediamine/epoxy resin system.
(2)Epoxy resin additives
Non-reactive end groups of the hyperbranched polymer does not react with the epoxy resin, curing agent, or the reaction activity is low. In epoxy curing system, the cured is modified by physical blending.
Hyperbranched polyester series.
Hydroxyl-terminated hyperbranched polyester can improve the tensile strength and impact strength of epoxy resin, adding the hydroxyl-terminated hyperbranched polyester of 10% mass fraction, the tensile strength and impact strength were increased by 17.7% and 26.3%, and after adding hyperbranched polyester, impact strength at low temperature is not lower than room temperature.
(3) Hyperbranched epoxy resin.
Epoxy-modified hyperbranched polyester can significantly improve the toughness of the epoxy resin coating, the impact resistance, along with the amount increase of the hyperbranched polyester, the impact resistance increases, while the dosage is 15%, the impact resistance is 296% of the original one and the rate of curing, mechanical strength of the original epoxy resin matrix are not affected, which is attributed to plasticizing properties of hyperbranched polyester and particulate structure in epoxy resin phase. Weihai CY Dendrimer Technology Co. Ltd.-Professional Manufacturer for low cost dendritic polymers