Polybenzoxazines-New high performance thermosetting resins : Synthesis and properties

Sulfonated hydrocarbon membranes for medium-temperature and low-humidity proton exchange membrane fuel cells (PEMFCs)

Preface 1 Introduction: 1.1 Background 1.2 Fire reaction and fire resistive properties of composites 1.3 Composites and fire 1.4 Case studies of composites in fire 1.5 Concluding remarks References 2Thermal Decomposition of Composites in Fire: 2.1 Introduction2.2. Thermal decomposition mechanisms of organic polymers 2/3 Rate processes and characterisation of decomposition 2.4 Polymers and their decomposition processes 2.5 Fire damage to composites 2.6 Concluding remarks References 3 Fire Reaction Properties of Composites: 3.1 Introduction 3.2 Time-to-ignition 3.3 Heat release rate 3.4 Extinction flammability index & thermal stability index 3.5 Mass loss 3.6 Smoke 3.7 Smoke toxicity 3.8 Limiting oxygen index 3.9 Surface spread of flame 3.10 Fire resistance References 4. Fire Modelling of Composites: 4.1 Introduction 4.2 Thermal exposure 4.3 Modelling material fire dynamics 4.4 Structural modelling of fire response References 5 Modelling the Thermal Response of Composites in Fire: 5.1 Introduction 5.2 Response of composites to fire 5.3 Modelling heat conduction in composites 5.4 Modelling the fire response of composites 5.5 Modelling the thermal properties of composites 5.6 Concluding remarks References 6. Structural Properties of Composites in Fire: 6.1 Introduction 6.2 Laminate properties 6.3 Measurement of elastic constants 6.4 Mechanical properties as a function of temperature 6.5 Modelling of properties 6.6 Fire resistance of laminates under load 6.7 Modelling of fire resistance of laminates under load 6.8 Concluding remarks References 7. Post-Fire Properties of Composites: 7.1 Introduction 7.2 Post-fire properties of laminates 7.3 Modelling the post-fire properties of laminates 7.4 Post-fire properties of sandwich composites 7.5 Post-fire properties of fire protected composites 7.6 Concluding remarks References 8 Flame Retardant Composites: 8.1 Introduction 8.2 The combustion cycle 8.3 Flame retardants for composites 8.4 Flame retardant fillers for composite 8.5 Flame retardant organic polymers for composites 8.6 Flame retardant inorganic polymers for composites 8.7 Flame retardant fibres for composites 8.8 Fire protective surface coatings References 9 Fire Properties of Polymer Nanocomposites: 9.1 Introduction 9.2 Characterization of nanocomposite formation 9.3 Evaluation of fire retardancy 9.4 Clay modifications 9.5 Examples of fire retardancy of polymer nanocomposites 9.6 Mechanisms of fire retardancy in nanocomposites 9.7 Future trends in fire retardancy of nanocomposites References 10 Fire Safety Regulations: 10.1 Introduction 10.2 Fire safety regulations for rail 10.3 Fire safety regulations for automobiles, buses and trucks 10.4 Fire safety regulations for civil infrastructure 10.5 Fire safety regulations for civilian aircraft 10.6 Fire safety regulations for ships and submarines References 11 Fire Tests for Composites: 11.1 Introduction 11.2 Scale of fire reaction tests 11.3 Cone calorimeter 11.4 Atmosphere controlled cone calorimeter 11.5 Intermediate-scale cone calorimeter 11.6 Ohio State University calorimeter 11.7 Limiting oxygen index test 11.8 Flame spread tests 11.9 Smoke density tests 11.10 Furnace tests 11.11 Burn-through & jet-fire tests 11.12 Single burning item test 11.13 Room fire tests 11.14 Structural integrity in fire tests 11.15 Aircraft fire tests 11.16 Concluding remarks References 12 Health Hazards of Composites in Fire: 12.1 Introduction 12.2 Smoke toxicity test methods 12.3 Health hazards of combustion gases 12.4 N-gas model for smoke toxic potency 12.5 Health hazards of fibres 12.6 Personal protective wear against burning composite materials 12.7 Concluding remarks References Subject Index

Fire Properties of Polymer Composite Materials

This paper presents a critical review of research progress in modelling the structural response of polymer matrix composites exposed to fire. Models for analysing the thermal, chemical, physical, and failure processes that control the structural responses of laminates and sandwich composite materials in fire are reviewed. Models for calculating the residual structural properties of composites following fire are also described. Progress towards validation of the models by experimental characterisation of the structural properties of composites during and following fire is assessed. Deficiencies in the fire structural models are identified in the paper, which provide the focus for future research in the field.

Review of fire structural modelling of polymer composites

Synthesis and thermal characterization of polybenzoxazines based on acetylene-functional monomers

Phthalonitrile polymers offer promise as matrix materials for advanced composite applications. The phthalonitrile monomer is readily converted to a highly crosslinked thermosetting polymer in the presence of thermally stable organic amine catalysts. Rheometric studies were conducted to elucidate the optimum amine concentration for composite formulations. High quality composite panels were processed in an autoclave using unsized IM7 carbon fibers. Mechanical properties of the phthalonitrile/carbon composite are either better than or comparable to the state-of-the-art PMR-15 composites. Dynamic mechanical analysis reveal that samples postcured at elevated temperatures (375°C) do not exhibit a glass transition temperature up to 450°C and also retain ∼90% of their initial modulus at 450°C. Flame resistance of phthalonitrile/carbon composites, evaluated by cone calorimetric studies, excels over that of other polymeric composites for marine applications. The composites also show low water uptake, <1% after exposure to water for 16 months.

Phthalonitrile-carbon fiber composites

Phthalonitrile polymers, under development at the Naval Research Laboratory, offer promise as high temperature, high performance composite matrix materials. A fully cured resin shows outstanding thermal stability with no evidence of a glass transition temperature or T g up to 450°C, good mechanical properties, and is easily processed into void-free components. Phthalonitrile/glass fabric composite panels have been successfully fabricated by conventional consolidation of prepregged glass and by a more recently developed simplified process, resin infusion molding. Both processes can be used to produce panels with comparable mechanical properties. More important, flammability performance of these composites, evaluated in terms of specific optical density, combustion gases, heat release, and ignitability, excels over other state-of-the-art polymer/glass composites. This finding is significant given that overcoming flammability obstacles has been the main limiting factor for use of composites in marine applications.

Phthalonitrile‐glass fabric composites

Isothermal spherulite growth rates were measured over a sufficient range of undercoolings, ΔT, for a narrow linear polyethylene fraction M = 70 300 (70.3K), polydispersity 1.12, such that the fraction exhibited all three growth regimes as crystallized from the subcooled melt. The I−II transition occurred at ΔTI-II = 15.8 °C and the II−III transition at ΔTII-III = 23.8 °C. (Neither transition was fully abrupt.) The nucleation constants Kg and preexponential factors G0 that described the absolute growth rates for each regime were determined, thus quantifying key parameters for all three regimes for a single specimen measured in the same apparatus. The Kg's for 70.3K conformed to the predicted relationship Kg(III) ≅ Kg(I) = 2Kg(II). Theoretical relationships for the preexponential factors were employed using the observed G0's to investigate the nature of the transport of chain segments to the growth front. It was reconfirmed that this process was forced “near-ideal” reptation for an M ≅ 30K fraction. For M =...

Direct Evidence of Regimes I, II, and III in Linear Polyethylene Fractions As Revealed by Spherulite Growth Rates

Cure studies of arylacetylene-terminated resins are described to gain some fundamental understanding of the influence of various structural aspects of a molecule on its cure chemistry. Of particular interest are the effects of the number of acetylenic substituents on the aromatic ring and their relative positions to one another. Activation energy (E) of the cure reaction as calculated from dynamic DSC analysis reveals that there is a direct correlation between the activation energy and the stability of radicals formed by thermal initiation. Based on model coumpound studies, it is evident that the resonance stabilization of radicals contributes significantly to the lowering of activation energy values

J. P. Armistead

Papers

Phthalonitrile-carbon fiber composites

Phthalonitrile‐glass fabric composites

Direct Evidence of Regimes I, II, and III in Linear Polyethylene Fractions As Revealed by Spherulite Growth Rates

Studies on cure chemistry of new acetylenic resins

Cure kinetics of a multisubstituted acetylenic monomer