Transparent low‐flammability epoxy resins with improved mechanical properties using tryptamine‐based DOPO derivative

Abstract

A novel flame-retardant hsaltryptamine phosphaphenanthrene (HTD) was successfully synthesized and characterized by Fourier transform infrared spectrometry and nuclear magnetic resonance. HTD was used to improve flame retardancy of epoxy resin (EP). When the addition content of HTD reached 4 wt%, the EP/HTD thermoset passed a UL-94 V-1 rating and had limited oxygen index value of 29.2%. Compared to neat EP, the release of heat and smoke decreased significantly due to the gaseous-phase and condensed-phase flame-retardant mechanism of HTD. The char residue after cone calorimeter test was analyzed and the results showed that the char residue of EP/8%HTD thermoset exhibited homogeneously crosslinked char layer, which acted as a good barrier for the release of heat and oxygen. The transmittance and mechanical properties of EP/HTD thermosets had been tested. EP/HTD thermoset possessed high transparency and good mechanical properties. In comparison to neat EP, tensile strength, flexural strength, and Izod unnotched impact strength of EP with 8% loading of HTD was improved by 21.9%, 20.5%, and 17.4%, respectively.

An Effective Method for Preparation of Liquid Phosphoric Anhydride and Its Application in Flame Retardant Epoxy Resin

“…The metaphosphoric acid was polymerized in the combustion and the subsequent formation of a char layer retained on the surface of combustibles prevented further heat transmission. 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) containing biphenyl, phenanthrene ring structures and the side phosphorus group in the form of active O=P-O cyclic bond was considered to be an effective reactive flame retardant substance for epoxy resins [ 16 , 17 , 18 ]. DOPO and their derivatives exhibited good thermal stability, chemical activity and flame retardant performance because of the embedment of a phosphorus atom into the epoxy molecular chain through chemical modification [ 19 , 20 , 21 ].…”

Reactive organophosphorus flame retardant for transparency, low‐flammability, and mechanical reinforcement epoxy resin

“…The 31 P NMR spectrum (Figure 1(b)) shows that the peaks of the chemical shifts of phosphorus in DPDDM were 28.4 and 31.3 ppm, respectively. The reason for the two chemical shifts for one kind of P atom can be contributed to the formation of stereoisomers caused by the steric hindrance in DPDDM 26 …”

“…The reason for the two chemical shifts for one kind of P atom can be contributed to the formation of stereoisomers caused by the steric hindrance in DPDDM. 26 As seen in 1 H NMR spectra (Figure 1(c)), the peaks at 9.5-9.2 ppm were attributed to Ar OH, and the peak at 8.3 ppm was assigned to N C H. Besides, the peaks of aromatic hydrogen were located between 7.4 and 6.7 ppm, and the double signal at 3.9 ppm was belonged to methylene ( CH 2 ). For DPDDM, the peaks at 8.9-8.7 ppm were attributed to Ar OH, and the peaks of aromatic hydrogen located between 8.2 and 6.2 ppm.…”

Thermo‐mechanical properties of rosin‐modified o‐cresol novolac epoxy thermosets comprising rosin‐based imidoamine curing agents

“…Additionally, the rosin modified novolac epoxy system (AEOCN) showed better mechanical performance than o‐cresol novolac epoxy (EOCN) that reveals strong and enhanced interactions between crosslinked polymer chains due to the presence of more epoxy groups. [ 41 ] Seok and Kim [ 42 ] performed mechanical tests on thermosets based on commercial DGEBA epoxy and synthesized bio‐based epoxidized soybean oil cured with commercial ethylene diamine. The results showed the tensile strength of 23 MPa for DGEBA based resin, which is much lower than AEOCN‐based thermosets.…”