Synthesis and physical properties of low‐molecular‐weight redistributed poly(2,6‐dimethyl‐1,4‐phenylene oxide) for epoxy resin

Abstract

Low-molecular-weight poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) was prepared by the redistribution of regular PPO with 4,4 0 -isopropylidenediphenol (bisphenol A) with benzoyl peroxide as an initiator in toluene. The redistributed PPO was characterized by proton nuclear magnetic resonance, mass spectra, and Fourier transform infrared spectroscopy. The redistributed PPO oligomers with terminal phenolic hydroxyl groups and low molecular weights (weight-average molecular weight ¼ 800-4000) were used in the modification of a diglycidyl ether of bisphenol A/4,4 0 -diaminodiphenylmethane network system. The curing behaviors were investigated by differential scanning calorimetry and Fourier transform infrared spectroscopy. The effect of molecular weight and the amount of redistributed PPO oligomers incorporated into the network on the physical properties of the resulting systems were investigated. The thermal properties of the cured redistributed PPO/epoxy resins were studied by dynamic mechanical analysis, thermal mechanical analysis, thermogravimetric analysis, and dielectric analysis. These cured redistributed PPO/epoxy resins exhibited lower dielectric constants, dissipation factors, coefficients of thermal expansion, and moisture absorptions than those of the control diglycidyl ether of bisphenol A based epoxy. The effects of the composition on the glass-transition temperature and thermal stability are discussed.

Low dielectric and flame‐retardant properties of thermosetting redistributed poly(phenylene oxide)

“…The dielectric constants and dissipation factors of the PO systems were lower than those of the TPP systems, regardless of the weight ratio of MA-PPO/TAIC. The dielectric characteristics of all MA-PPO/ TAIC systems were significantly lower than those of the DGEBA/DDM epoxy system (D k [11]. This difference is attributed to the low polarity and hydrophobic structure of the PPO chain.…”

“…Low-molecular-weight PPO was obtained from the free-radical redistribution reaction of MA with regular PPO in the presence of BPO as an initiator [10,11]. The decrease in molecular weight dur-ing the redistribution reaction was followed by GPC, as shown in Fig.…”

“…The aromatic ring stretching of the PPO led to absorption at 1610 cm 21 . Upon comparing the FTIR spectrum of redistributed PPO with that of the original PPO, small differences at around 1740 and 1725 cm 21 , representing carbonyl absorptions, were observed [11].…”

Preparation and characterization of nanocomposites with polyphenylene oxide

“…Some other telecthelic polymers with good thermal and chemical stabilities have also been synthesized by using PPO as backbone with other functional groups (Hwang et al, 2008b;Lee et al, 2007a). Thermal analysis results indicate that the values of T g for polymers are generally higher than those of conventional low molecular grades of PPO and the incorporation of a bulky or rigid rod structure enhanced the thermal stability of resulting polymers.…”

Compatibilized the thermosetting blend of epoxy and redistributed low molecular weight poly(phenylene oxide) with triallylisocyanurate

“…6,14 In order to obtain high performance thermosetting EP/PPO system, it is extremely essential to improve the compatibility between EP and PPO resin. Some efficient methods include reducing the molecular weight of PPO [15][16][17] or adding reactive monomers as compatibilizer to EP/PPO system. Triallylisocyanurate (TAIC) has good compatibility with EP and also contains three allyl groups which could react with various molecules or self-polymerize to form a network.…”