Reporter:Chen-Kun LinAdviser:Cheng-Chien Wang

2011.06.28

• Epoxy resins have dimensional stability, satisfactory mechanical properties, so that they are widely used as coating, adhesion, lamination, casting and electronic encapsulation materials.

• However, the flammability of epoxy resins is a major problem in applications where high thermal and flame resistance are needed.

• Many approaches have been used to improve the flame retardancy of epoxy-resin composites.

Introduction

• A feasible way to reduce flammability of epoxy-resin composites is the utilization of flame-retardant agents or fire-resistant curing agents.

• Still commonly used are halogenated flame retardants, which appear to function principally by reacting with radicals produced during combustion (mainly H+ and OH-), generating less-reactive halogen radicals.

• However, these reactions result in the release of toxic, corrosive, halogenous gases, such as hydrogen chloride.

Introduction

• Consequently, low or zero use of halogen in flame retardants is the current trend.

• Increasing use is being made of phosphorus-containing flame retardants.

• The objective of this investigation is to reduce flammability of epoxy-resin composites using an anhydride with a pendent phosphorus and halogen-free group.

Introduction

Materials

9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO)

Itaconic acid

Hexahydrophthalic anhydride (HHPA) and phthalic anhydride (PA)

N-Benzyldimethylamine (BDMA)

Tetrahydrofuran and n-hexane

Experimental

Synthesis of (9 ,10 -dihydro -9 -oxa -10 -phosphaphenanthrene -10 -oxide ) methyl succinicanhydride (DMSA)

Experimental

Curing of epoxy networks

The mixture was continuously stirred and then placed in an oven at the desired curing temperature (130 ).℃The samples were cured in a hot press at 130 for 3 hr followed by ℃2 hr post-cure at 170 .℃

Results and discussion Monomer synthesis and characterizations

Results and discussion Monomer synthesis and characterizations

Results and discussionThermal properties

Results and discussionThermal properties

Results and discussionThermal properties

Results and discussionFlame properties

Results and discussionFlame properties

• An aryl phosphinate anhydride (DMSA) was synthesizedby the addition and dehydration reaction of DOPO with itaconic acid.

• The a major degradation of those epoxy-resin composites took place in the same temperature range (350-450 ),and the initial ℃decomposition temperature was not significantly shifted.

• Epoxy resins cured with DMSA exhibit higher LOI values and char yields compared with those cured by commercial curing agents, such as PA and HHPA.

Conclusions

• Furthermore, the LOI value and the char yield of the epoxy-resin composites increased with increasing phosphorus content.

• The utilization of appropriate amounts of DMSA in the epoxy systems would give good flame retardancy.

Conclusions

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