Urea‐activated 4,4'‐oxibis‐(benzenesulfonyl hydrazide) as foaming agent for low‐density unsaturated polyester resin manufacturing

Abstract

The activation of foaming agent is critical to its application. In this study, 4,4 0 -oxibis-(benzenesulfonyl hydrazide) (OBSH) activated by urea was used in the manufacture of low-density unsaturated polyester resin (LDUPR), and the results were compared with that of OBSH activated by zinc oxide and zinc stearate. The experiment results showed that the activation of OBSH by urea was better than by zinc oxide or by zinc stearate. A novel hydrogen bond activation mechanism of urea is presented in this research. Two stages, including the induction stage and the foaming stage, were proposed in the LDUPR manufacture according to the gas evolution curves of activated OBSH. The decomposition temperature and the decomposition time of OBSH activated by urea were determined to match the gelation time of UPR for the manufacture of LDUPR. The disadvantageous chemical behaviors of activated OBSH were eliminated in the induction treatment. The activated OBSH via induction treatment released gas maximally and distributed gas homogeneously in the resin glue, resulting in a better foaming effect than that of the previous foaming agents.

High Mechanic Enhancement of Chopped Carbon Fiber Reinforced-Low-Density Unsaturated Polyester Resin Composite at Low Preparation Temperature with Facile Polymerization

“…Different apparent densities of low-density unsaturated polyester resin samples were calculated and were in the range of 0.41~0.50 g·cm −3 with the presence of 2.00 phr NH 4 HCO 3 at temperature from 52.0 to 60.0 °C. These calculated values of apparent density matched those of low-density material in References of [ 5 , 18 , 19 ], which were between 0.30 g·cm −3 and 1.00 g·cm −3 . Therefore, 52.0~60.0 °C was set as the curing temperature for CCFR-LDUPR samples preparation.…”

Mechanical enhancement of ripples and dimples in CaCO3/low-density unsaturated polyester resin composites

“…Orthogonal experiment is a kind of multifactor and multilevel test design method, which can substantially reduce the number of tests under the condition of ensuring the representativeness of the test [23,24]. In this study, an orthogonal experiment of L 25 (5 3 ) (where L is the code name, 25 is the number of test, 3 is the number of different factors, and 5 is the level number for one factor [3,5]) was designed for the preparation of CaCO 3 /LDUPR. X, Y, and T were three different factors.…”

“…The preparation of LDUPR and its composite materials have progressed over the past decade. Guo et al [4], Zhang et al [5] and Ji et al [1] presented new organic foaming methods or novel mechanisms of LDUPR preparation. Xu et al prepared LDUPR utilizing the cooperation of sodium bicarbonate and azodiisobutyronitrile [2].…”

Low-Density Unsaturated Polyester Resin with the Presence of Dual-Initiator

“…Among different curing processes of UPR at different temperatures, there were three different types of initiators, which were low-temperature (40–70 °C) initiators [ 4 , 12 , 13 , 14 , 15 ], medium-temperature (70–130 °C) initiators [ 16 , 17 , 18 , 19 ], and high-temperature (≥130 °C) initiators [ 20 , 21 , 22 , 23 ]. Regarding commercial low-temperature initiators, there are cyclohexanone peroxide (CYHP), methyl ethyl ketone peroxide (MEKP), and benzoyl peroxide (BPO), which were applied together with accelerators [ 12 , 24 ].…”