Interactions between chlorinated paraffins and melamine in intumescent paint—investing a way to suppress chlorinated paraffins from the formulations

It is known that acid source, carbon source and blowing agent are the main ingredients of an intumescent paint. Melamine and halogenated additives, such as polychlorinated alkanes (PCAs) are used as blowing agents, however, the legislation tends to prohibit the use of halogenated coumpounds for environmental reasons. The aim of our study is to investigate the mode of action of melamine and PCAs in an intumescent formulation. Their interactions are also studied. It is found that the combination of PCAs and melamine leads to more efficient systems. Spectroscopic analyses (FTIR and solid state ¹³C NMR) led us to conclude that when the intumescent paint was heated melamine condensed to create melem via Diels-Alder-type reaction. Melem could then react with PCAs leading to the stabilisation of the PCA-melamine mixture. The proposed mechanism of action led us to propose a method for the substitution of PCAs.     

Intumescence: Tradition versus novelty. A comprehensive review

The objective of current research on intumescent formulations is on consolidated approaches for conferring flame retardancy properties to polymers and polymer blends. Numerous academic and industrial efforts have been carried out in the last fifteen years, by revisiting the traditional concept of intumescence on the basis of the new chemical synthesis or novel nano-technological developments. The main concepts of intumescence are reviewed in this report, highlighting the novelties as well as the most significant results achieved in the flame retardancy of polymeric materials in the last 10–15 years. Although the basic aspects of intumescence such as the chemical components, thermal and rheological aspects are well-known, the modeling and simulation of these systems are completely new and never reviewed. Analogously, the traditional chemical compositions will be compared with the novel systems, most of them based on the nanotechnology and synergistic aspects. Thus, the results collected up-to-now by using these new intumescent formulations will be dealt with the different polymer families. The use of current intumescent coatings for metals, steel, wood and plastics as well as the application of novel intumescent coatings deposited on fabrics, films and foams through layer-by-layer assembly are reviewed. Although the latter technique is not new, its use to confer flame retardancy properties to polymers is a recent development.     

Carbonization mechanisms resulting from intumescence association with the ammonium polyphosphate-pentaerythritol fire retardant system

In this work we study the thermal behavior of an ammonium polyphosphate-pentaerythritol mixture, fire-retardant additive for polyolefins and most particularly the carbonization process resulting from an intumescent phenomenon. The study has been carried out using Micro-Raman and ¹³C, ¹H, ³¹P NMR of the solid state spectroscopies. It is shown that the structure consists in phoscarbonaceous and polyaromatic species. These latter form an anisotropic structure above 280°C. This structure grows when the temperature increases. Finally, a reactional scheme of the carbonization of the intumescent system is proposed.     

Controlled atmosphere pyrolysis apparatus II (CAPA II): A new tool for analysis of pyrolysis of charring and intumescent polymers

A new gasification apparatus has been developed to enable a comprehensive analysis of pyrolysis of charring and intumescent materials. This apparatus provides well defined boundary conditions and highly resolved measurements of mass, temperature and sample profile evolution of a disk-shaped 0.07 m diameter material sample exposed to radiant heat. All measurements are collected simultaneously, in a single experiment, and recorded as a function of time. The oxygen concentration in the pyrolysis zone is controlled and can be reduced below 1 vol% to ensure that the measurements are free of oxidation effects. The radiation from an external conical heater has been carefully characterized to account for changes in the sample surface position, including the surface's angular orientation. Using an empirical expression, the radiation heat flux can be predicted with less than 2% error based on the known surface position and heat flux set point. The NIST Fire Dynamics Simulator (FDS) has been utilized in the direct numerical simulation mode to investigate convective losses from the sample surfaces. The convective heat transfer coefficient computed for the top (radiation exposed) surface has been found to be dependent on the surface position; its space-averaged value has been validated against experimental measurements. The capabilities of the apparatus are demonstrated using poly(vinyl chloride). It is shown that the apparatus provides repeatable data necessary for modeling of transport processes inside pyrolyzing intumescent solids. Non-one-dimensional nature of these processes is discussed.     

硅丙乳液膨胀型防火涂料的研制

叙述了硅丙乳液膨胀型防火涂料研制过程中的材料选择、工艺设计及配方优化。对该涂料的理化性能、技术指标等进行了全面讨论。该防火涂料的特点是：不但防火性能好、不污染环境、适用范围广，而且装饰效果好，具有普通涂料的装饰水平。     

Structural Basis for Intumescence – Part III – Thermal Degradation Study of Intumescent Polymers Containing Spirophosphorus Moiety in the Backbone

3,9-Dichloro-2,4,8,10-tetraoxo-3,9-disphosphaspiro-[5.5]-undecane-3,9-dioxide (spiro) was melt condensed with structurally different dihydric phenols to form poly aromatic spirophosphates. The thermal volatilization analysis showed eruptive release of gases above 300°C and the temperature region of release depends on the nature of the aromatic units incorporated in the polymer backbone. The thermal degradation in nitrogen atmosphere indicated the formation of phenol, substituted phenols, aromatics, alkyl and alkenyl substituted aromatics and condensed aromatics like azulenes, indanes and fluorenes. The source for the formation of these products is the spiropentadiene released from the spiro unit during degradation.     

IFRC—871饰面膨胀型防火兴料的研制

研制的新型IFRC-871饰面型水性膨胀型防火涂料,具有优良的防火性能和普通饰面漆的装饰作用,其耐火和装饰性能超过目前市售的防火涂料,它还可用作钢结构防火涂料.该涂料以双氰胺-尿素-甲醛树脂为基料,研究了基料合成反应的机理和方法;用正交设计方法确定了最佳配方,在最佳配方和涂覆比为3.0kg/m2(涂层厚度小于<3mm)时,耐燃时间可达到300min;考察了基料、颜填料和成炭剂用量对涂料耐火性能的影响.该涂料具有涂层薄、省工省时、附着力强、适用范围广等特点.其为水基涂料,不含有机溶剂,为绿色环保型产品.     

Structural Basis for Intumescence—Part II: Synthesis and Characterization of Intumescent Polymers Containing Spirophosphorus Moiety in the Backbone

Taking the spirophosphorus compound 3,9-dichloro-2,4,8,10-tetraoxo-3,9-diphosphaspiro-[5,5]-undecane-3,9-dioxide as one of the reactive monomers, a family of aromatic spirophosphates was synthesized using dihydric phenols, viz., resorcinol, hydroquinone, 4,4′–dihydroxydiphenyl, bisphenol-A and fluorene dicarbinol as the other monomers. The polymers were synthesized employing melt condensation technique under vacuum and characterized using FT-IR, ¹H-, ¹³C- and ³¹P-NMR spectroscopic methods. The number average molecular weight of the polymers was determined using vapour phase osmometry. Thermal properties of the polymers were studied using differential scanning calorimetry and thermogravimetry techniques. These studies indicated that the polymers containing spirophosphato moiety undergo eruptive degradations in the temperature region 310°–380°C leading to the formation of dense carbonaceous foam. The present study confirmed the spirophosphate structure as an essential requirement to show intumescence.     

Prediction of the burning rates of charring polymers

A quantitative understanding of the processes that take place in the condensed phase of a burning material is critical for prediction of ignition and growth of fires. In the current study, a model of burning of two widely-used charring and intumescing polymers, bisphenol A polycarbonate and poly(vinyl chloride), was developed and validated. The modeling was performed using a flexible computational framework called ThermaKin, which had been developed in our laboratory. ThermaKin solves time-resolved energy and mass conservation equations describing a one-dimensional material object subjected to external heat. Most of the model parameters were obtained from direct property measurements. The model was validated against the results of cone calorimetry experiments performed under a broad range of conditions. Potential sources of uncertainties in the model parameterization were analyzed.     

Soluble silicate-based coatings for fire protection

A fire protective coating based on a soluble silicate was investigated in terms of intumescence, water sensitivity, and water absorption versus relative humidity. An acidic curing agent was used to improve the coating performance. The mechanism of intumescence of the silicate-based material was studied using DSC and TGA techniques.