The history of polymer fire retardance is reviewed from its inception with the early Egyptians to the most recent developments in intumescent fire retardants and inherently fire retardant polymers. EARLY HISTORYThe control of polymer flammability, which has enjoyed considerable success in the last forty years, had its beginnings in antiquity with the first early attempts to reduce the flammability of natural cellulosic materials such as cotton and wood (1-3) .Some of these early developments are summarized in Table I. Perhaps the earliest reference to this development was reported by the Greek historian Herodotus (484-431 BC) who noted that the Egyptians were imparting a degree of fire retardance to wood by soaking it in alum (potassium aluminum sulfate). About two centuries later, the Romans "improved" the process by adding vinegar to the mixture.Military applications for fire retardant wood were subsequently reported in the first century B.C. by Vitruvius where early siege towers were protected against incendiaries by a thick coating of clay reinforced with hair. An "incombustible cloth" was subsequently developed in the 17th century for Parisian theater curtains by treating canvas with a mixture of clay and gypsum.The first patent on a fire retardant treatment for wood and textiles was issued to Wyld in 1735.

SynopsisThe mechanism of the low profile behavior in certain single-phase polyester systems has been examined. It appears that as polymerization occurs, crosslinked beads (

SynopsisThe mechanism by which low profile character is achieved in unsaturated polyester systems has been investigated. Using techniques of microscopy, data are developed that support a model in which micro stress cracking is induced to relieve stress promoted by polymerization shrinkage. Thus the strain is accommodated internally in a molded part, rather than through macroscopic shrinkage of the article.

Viscosity, number‐average and weight‐average molecular weights (measured by gel permeation chromatography), and carbon‐13 nuclear magnetic resonance (NMR) were used to monitor the changes in phenolic resoles as a function of time and pH. It was observed that phenolic resoles with pH around 5 are more stable, as indicated by the lowest increase in viscosity and molecular weight. Carbon‐13 NMR spectroscopic studies also suggest that the concentration of methylol groups is higher for resoles with pH around 5 and, thereby, indicate a slower reaction.

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