Grantee Research Project Results

Final Report: Novel ‘Greener’ Routes to Halogen-free Flame Retardant Materials

EPA Grant Number: SU834738
Title: Novel ‘Greener’ Routes to Halogen-free Flame Retardant Materials
Investigators: Nagarajan, Ramaswamy , Kumar, Jayant , Bouldin, Ryan , Ravichandran, Sethumadhavan
Institution: University of Massachusetts - Lowell
EPA Project Officer: Page, Angela
Phase: I
Project Period: August 15, 2010 through August 14, 2011
Project Amount: $9,999
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2010) RFA Text |  Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , P3 Challenge Area - Chemical Safety , P3 Awards , Sustainable and Healthy Communities

Objective:

Over the last two decades, the increased consumption of polymeric materials has resulted in rapid growth of the additive industry, particularly flame retardants. Flame retardant (FR) materials are external additives that control or reduce/eliminate the risk of fire growth in inherently flammable polymeric materials. The most commonly used FR additives are halogen based compounds, due to their excellent effectiveness, easy processability and low cost. However halogenated FRs are slowly released over the lifetime of the polymeric matrix in the environment, making their way up the food chain and eventually accumulating in humans. In addition, they are extremely toxic and cause damage to immune, reproductive, nervous, and endocrine systems on exposure. With several environmental organizations posing stringent limitations and bans on the usage of these materials, there is a tremendous need for the development of alternative materials, preferably from non-toxic approaches. This research project will use methodologies that are in accordance to the 12 principles of green chemistry and benefit the three pillars of sustainability – people, prosperity and planet.

The primary objective of the proposed research is to develop a simple, non-toxic technology for the development of less-toxic flame retardants. Specific goals of the project are stated in the list below.

• Phenol and its derivatives were used as starting materials to synthesize polyphenols, as they satisfy two primary criteria necessary for good flame retarding capability; thermal stability with char and radical scavenging capability. Renewable resources like cardanol, obtained from cashew nut shell liquid and structural components of lignin were used as starting materials for polyphenol synthesis.
• The use of polymeric materials reduces diffusion of the additive over time to the surface of a polymeric matrix, thereby eliminating exposure and the possibility of bio-accumulation in humans.
• Another important goal of this project is the use of environmentally benign biocatalysts and cost effective biomimics to accomplish simple, one pot polymerization reactions.
• The success of the synthesized FR materials was evaluated based on thermal stability, char forming capability and heat release capacity values obtained for thermal characterization using thermogravimetric analysis and calorimetric studies.

Summary/Accomplishments (Outputs/Outcomes):

• Phenol monomers from renewable resources like cardanol and its derivatives and synthetic monomers like 3-(4-hydroxyphenyl)-1-propanol (HPP) and 2,6-dimethylphenol were selected as starting monomers for polyphenol synthesis.
• Polymerization reactions were accomplished using biocatalytic and biomimetic catalysts like peroxidases (horseradish and soybean) and iron porphyrins (hematin and iron salen) respectively. in a simple one step procedure. Structural characterization techniques like FTIR were used to estimate the structure of the synthesized products.
• Thermal characterization of poly(cardanol) based materials revealed the formation of high char yields (~ 20% at 900°C). They exhibited low heat release capacities (200-250 J/gK) comparable to PEEK, exhibiting characteristic of a good flame retardant material.
• Polyphenols based on HPP were extremely thermally stable, exhibiting very high char yields (>40% at 900°C) and very low heat release capacities (93 J/gK) and can be categorized as ultra fire resistant material, as per Lyon et al’s classification.
• Preliminary lab scale vertical burn tests on polyphenol FR coated samples exhibit good promise, increasing burn times by two times in comparison to uncoated samples.

Conclusions:

In phase I, we have successfully accomplished the synthesis of a novel class of non-halogenated FR materials based on polyphenols. The use of biocatalysts and biomimics coupled with renewable and biodegradable starting materials directly benefits the three pillars of sustainability – people, prosperity and planet. The flame retardancy of the synthesized materials in terms of the heat release rates and heat release capacities are comparable to good fire-retardant plastic materials. In phase II, we would like to extend the success of these experimental results to real life performance in plastic products. This would a significant step forward in trying to replace the currently used toxic halogenated FR additives.

Journal Articles on this Report : 1 Displayed | Download in RIS Format

Publications Views

Other project views:	All 1 publications	1 publications in selected types	All 1 journal articles

Publications

Type	Citation	Project	Document Sources
Journal Article	Kiratitanavit W, Ravichandran S, Xia Z, Kumar J, Nagarajan R. Thermally stable polymers of cardanol as char-forming additives for polypropylene. Journal of Renewable Materials 2013;1(4):289-301.	SU834738 (Final) SU835071 (Final)	Full-text: Journal of Renewable Materials - Full Text HTML Exit

Supplemental Keywords:

Enzymatic polymerization, biocatalytic, non-halogenated flame-retardants, renewable feedstocks, green chemistry, biomimetic catalyst, cardanol, sustainable environment, peroxidase, polyphenol-nanoclay, green chemistry, environment friendly chemical synthesis, alternative materials, pollution prevention, technology for sustainable environment

Relevant Websites:

Novel 'greener' routes to halogen-free flame retardant materials Exit

P3 Phase II:

Novel 'Greener' Routes to Halogen-Free Flame Retardant Materials  | 2013 Progress Report  | Final Report