dc.description.abstract | The preparation and application of halogen-free flame retard polymer becomes the major concern of environment friendly study in recent years, mostly researches put the attention in radical trapping reaction with appropriate structures, efficient flame-retard layer by continuous surface char-forming, and the thermal stable units contribute to heat resistance. There are still have some problems lead to the negative influences including higher H2O absorption, lower flexibility and modulus, destruction of electrical properties, and ease to phase separation in hybrid polymer, although the presented the excellent flame retardancy. The approaches of our study in the novel halogen-free flame retard polymers will settle on few ways such as (1) higher aromatic content, (2) increased cross-linking density, (3) accelerated the char yielding, and (4) inflammable organic volatiles release. They are possible to anticipate in heat resist, oxygen dilution, thermostability, and stable mechanical properties.
In this report we follow the concepts aforementioned to prepare novel novolac resins which present higher density and toughness, the structure and characteristics are examined to realize the solubility, molecular weight and thermal kinetics at first, followed by the study in morphology, thermal characteristics and degradation kinetic to identify the structural reaction, degradation active energy change and the weight loss conversion, etc. Furthermore, physical properties are discussed detailed in the difference of loss modulus, storage modulus and thermal expansion using dynamic mechanical analysis or thermal mechanical analysis. The complex hybrid-polymer system with epoxy resin or inorganic filler is developed in advanced experimental by various weight ratio with IR and solid-state NMR to understand the influence of compatibility, and then the results and discussions of complex hybrid polymers will be presented correspondingly. It is necessary to understand the flame retardancy with novel modified novolac resins about techniques and concepts, for the further application widely in other kinds of halogen-free polymer, effective estimation will leads to the higher performance polymeric materials.
Furthermore, flame retardancy can be made more pronounced by combine the inorganic filler to polymer complex. In contrast with blank, the obvious effect due to decreased burning time under 35 sec. at the initial content, and show the degree by CHABN > HPDEN > CPAN. Therefore, they show the V0 degree laminates only when filler content around 45 ~ 50 wt. % in contrast with the blank series (70 wt. %). On the other hand, the CPAN and HPDEN series show the burning time around at 5 ~ 6 sec. and the CHABN series is nearly zero. It indicates the effective flame retardancy of highly thermostable polymers can be achieved with lower inorganic filler content when using modified phenolic. They will display effective heat or flame barrier property through some possible mechanisms such as sharing the heat of polymer by inorganic filler, flame restricted by organic-inorganic hydride structure, and highly / quick char formation.
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