Preparation and characterization of epoxidate poly(1,2‐butadiene)–toughened diglycidyl ether bisphenol‐A epoxy composites

Abstract

By the oxidation of liquid poly(1,2-butadiene) (LPB) with H 2 O 2 /HCOOH, epoxidate poly(1,2-butadiene) (ELPB) was obtained as a toughening agent to prepare diglycidyl ether bisphenol-A (DGEBA) epoxy composites by using V115 polyamide(PA) as a cross-linking agent. DGEBA, ELPB, and the composites were effectively cured by PA at 100 C for 2 h followed by postcuring at 170 C for 1 h. Thermal gravimetric analysis results in air and nitrogen atmosphere showed that the thermal stability of composites could be improved by the addition of ELPB. Compared with DGEBA/PA, the composites exhibited a decrease in strength at yield but an increase in strain at break with the increase in ELPB amount. The composite with 10% ELPB exhibited both thermal stability and tenacity superior to those of DGEBA/PA and composites with 5 and 20% ELPB, respectively. The improvements in thermal and mechanical properties of composites depended on the formation of Inter Penetrating Networks (IPN) among DGEBA/ PA/ELPB and their distributions in the matrix. At an appropriate ELPB amount, the IPN, mostly made of DGEBA/PA/ELPB, may be distributed more evenly in the matrix; less ELPB resulted in the formation of IPN mainly made of DGEBA/PA; excessive addition of ELPB resulted in the local aggregation of ELPB/PA and phase separations. The toughening mechanism was changed from chemically forming IPN made of DGEBA/PA/ELPB to physically reinforcing DGEBA/PA by ELPB/PA with the increase in ELPB addition.

Preparation of silica/epoxy hybrid polymers as sealing layers on ceramic coatings and their stability study upon thermal treatment

“…These hybrids exhibit thermal decomposing behaviors different from both the neat epoxy and most inorganic/polymer blends. It is considered that the first rapid decomposition is the breakdown of the aliphatic group, and the second rapid decomposition originates from both the benzene ring in the epoxy resin and the stable compound formed by the heteroatoms in the first stage . In general, inorganics as inert and thermal insulating fillers can improve the thermal stability of inorganic/polymer blends; however, with much more silica addition in the hybrids, this did not happen in this study.…”

“…It is considered that the first rapid decomposition is the breakdown of the aliphatic group, and the second rapid decomposition originates from both the benzene ring in the epoxy resin and the stable compound formed by the heteroatoms in the first stage. 26,27 In general, inorganics as inert and thermal insulating fillers can improve the thermal stability of inorganic/polymer blends 28,29 ; however, with much more silica addition in the hybrids, this did not happen in this study. During heating, some contradiction phenomena occur: the silica gel continues its condensation to form silica, expediting the weight loss; the silica gels and the asformed silica have a function of thermal insulation to protect the polymer chains from decomposition, retarding the weight loss.…”

Preparation and characterizations of RTV epoxy blends using amide maleic anhydride‐g‐liquid polybutadience as both reactive toughening and curing components

“…Figure presents the TGA curves for neat epoxy and the blends, their weight loss (TG) (a) and the rates of weight loss (DTG), (b) with temperatures, respectively. The first rapid decomposition temperature for the blends and neat epoxy appeared at 290 °C, indicates the aliphatic groups breaking in the matrix, whereas the second fast decomposition temperatures appeared at 520 °C, is generally considered as the fast decompositions of benzene ring of EP and stable complex compounds formed by heteroatoms residues in the first stage . In the testing range, all the samples exhibit similar decomposing behavior; they do not exhibit much difference in the weight loss and the rate of weight loss upon heating due to the similar aliphatic groups from EDA and AMALPB.…”

“…The first rapid decomposition temperature for the blends and neat epoxy appeared at 290 8C, indicates the aliphatic groups breaking in the matrix, whereas the second fast decomposition temperatures appeared at 520 8C, is generally considered as the fast decompositions of benzene ring of EP and stable complex compounds formed by heteroatoms residues in the first stage. 23,24 In the testing range, all the samples exhibit similar decomposing behavior; they do not exhibit much difference in the weight loss and the rate of weight loss upon heating due to the similar aliphatic groups from EDA and AMALPB. These thermal analysis curves suggest that the addition of AMALPB would not reduce the thermal stability of the blends.…”