Fire retardant and environmental impact of polymer additives

KEJ4604 POLIMER DAN ALAM SEKITARTahun 3 [Semester 6]

Kumpulan 4UK31701 MOHAMAD ZARIF BIN ABDULLAH SHOKRI

UK31514 ABDUL MUN'IM BIN RAMLIDate : 25/04/16

TOPIC

1. Fire Retardants of Polymer Materials

2. Environmental Impact of Polymer Additives

World Synthetic Polymers Production in 2007

World Plastics Production 1950 - 2007

Why are Additives added to Polymers?

Three Functional Classes for Additives:• 1) Additives which are essential to fabrication

of parts• 2) Those which improve properties• 3) Those which correct problems caused by

the other additives !

Compounding of Additives into Polymers

Example of Additives used in Plastics

• Mineral Reinforcement/Fillers: improve stiffness, surface hardness, cost reduction

• Dyes and Pigments: color & appearance• Antioxidants & stabilizers: delay/prevent oxidation during processing/application• UV Stabilizers: interfere with light-induced degradation, weathering• Blowing Agents: production of foams, weight reduction• Lubricants: improvement in processing, release properties• Coupling Agents: impart compatibility between polymer & additives• Antistats/Conductives: prevent electrostatic discharge, improve conductivity• Antimicrobials: prevent microbiological attack and property degradation• Impact Modifiers: enhance toughness of material to impact• Optical Brighteners: enhance appearance, off-set yellow color• Fire Retardants: prevent ignition & flame spread, prolong escape time

What are Fire Retardants?

• Fire retardants are chemicals which are added to many materials to increase their fire safety. For example, many plastics are highly flammable and therefore their fire resistance is increased by adding flame retardants in order to reduce the risk of fire.

Limiting Oxygen Index (LOI)

Fire Retardant Selection Criteria• Efficiency/Cost• Ease of Compounding• Adequate Thermal Stability• Corrosivity Issues• Physical Properties• Appearance• Compatibility (Migration?)• Environment/Toxicity• UV Stability/Weathering• Electrical Properties• Combustion Products (corrosives, toxics, smoke)

Example Structure of Fire Retardants

Ignition Inhibitors

• An important way of inhibiting the ignition of polymeric materials is to increase the formation of carbonaceous ‘chars’ at the expense of combustible fuels.

• Ammonium phosphate has been used for many years as a flame retardant for cotton and is known to work by catalyzing the formation of carbon and water

Cont.

• effective in poly(urethane) foams which form a major component of much domestic upholstery

• Ammonium polyphosphate appears to cross-link the polymer at high temperatures, thus increasing the probability of carbon-carbon bond formation in the condensed phase

Vapour Phase Retarders

• Bromine compounds and to a lesser extent chlorine compounds are known to be inhibitors of the branching radical chain reactions that occur in flames

• H+ + 02 - *O+ + *OH

• *OH + CO - H* + CO2

Cont.

• Hydrogen chloride and hydrogen bromide both inhibit these reactions by being converted into the relatively unreactive halogen atoms (X.) and may be looked upon as high temperature chain-breaking antioxidants

• H* + HX ------+ H2 + X*

• *OH + HX - H20 + X.

• Hydrogen halides have to be released over a wide temperature range for maximum effectiveness

• and this is achieved using the synergist, antimony triode (Sb,O,) which, although ineffective by itself,

• increases the effectiveness of bromine-containing flame retardants almost three times.

• It is believed that more thermally stable antimony bromides are formed

• which partially replace hydrogen bromide in the gas phase:

• SbBr3 + H* - SbBr2 + HBr

Inert Gas Generators

• Water vapour is an excellent flame extinguisher because it vaporises with the absorption of heat and then excludes oxygen from the site of the fire

• A similar principle has been developed by incorporating hydrated metal oxides that liberate water under combustion conditions

Global Consumption of Flame Retardants (2007)

Global Flame Retardant Market• Recent BCC Research Study: the global market for flame retardant chemicals will

grow to $6.1 B in 2014 (Compound annual growth rate of 7%).

Fire Retardants Consumption by Region global consumption

Global FR Uses by Polymers all applications

Fire Retardant Consumption by final application

Concerns about Fire Retardants

• findings of certain brominated flame retardants in the environment, biota, humans

• some concern about certain phosphate esters in indoor air

• source of endocrine disruption ?• FR Persistence, Bioaccumulation, Toxicity (PBT) ?• risk assessments, scientific studies for materials

of concern

Ignition Source in contact with Household Appliances (non-Fire Retardant)

Conclusion• Plastics are widely used in our society. The global

consumption of plastic materials is increasing. New materials and applications are being developed.

• It is necessary to add Fire Retardants to some plastics (dependent on application).

• Fire retardant consumption is growing globally due to increased standard of living and fire safety requirements..

• There is a trend towards more environmentally compatible • Fire Retardants additives are beneficial to prevent ignition,

flame spread & prolong escape time.

ENVIRONMENTAL IMPACT OF POLYMER ADDITIVES

Introduction

additive (in polymer)-Substance added to a polymer.

Polymer Additive - A chemical or other material added to a polymer formulation in order to change the end property or properties of the polymer product.

Introduction

polymer additive is usually a minor component of the mixture formed and usually modifies the properties of the polymer.

Examples of polymer additives are antioxidants, plasticizers, flame retardants, processing aids, other polymers, colorants,

UV absorbers, and extenders.

Main functions of polymer additivesMain function Agents

Polymerisation/chemical modification aids • Accelerators • Cross-linking agents• Chain growth regulators • Promoters• Compatibilisers

Improvement in processability and productivity (transformation aids)

• Defoaming and blowing agents• Flow promoters• Plasticisers • Thixotropic agents, thickening agents• Processing aids• Release agents

Increased resistance to degradation during processing or application

• Acid scavengers • Metal deactivators• Biostabilisers Processing/thermal • Stabilisers• Light/UV stabilisers

Main functions of polymer additivesImprovement/modification of mechanical properties

• Compatibilisers • Impact modifiers (elastomers)• Cross-linking agents• Nucleating agents• Fibrous reinforcements (glass, carbon) • Plasticisers or flexibilisers• Fillers and particle reinforcements

Improvement of product performance • Antistatic agents • Friction agents• Blowing agents• Odour modifiers• EMI shielding agents• Plasticisers• Flame retardants• Smoke suppressants

Main functions of polymer additivesImprovement of surface properties • Adhesion promoters

• Lubricants Antifogging agents • Slip and antiblocking agents• Antistatic agents• Surfactants• Antiwear additives• Wetting agents• Coupling agents

Improvement of optical properties • Nucleating agents • Pigments and colorants• Optical brighteners

Reduction of formulation cost • Diluents and extenders • Particulate fillers

Needs of Polymers Additives

• improve performance and/or durability.• Polypropylene is an outstanding example showing

how polymer additives can change a vulnerable and unstable macromolecular material into a high-volume market product.

• Increase resistance to heat, light , flame retardancy, electrical conductivity,

• Higher service temperature, dynamic and mechanical strength, stronger resistance against chemicals or radiation, and odourless formulations.

ENVIRONMENTAL IMPACT OF POLYMER ADDITIVES

• arylamine antioxidants for rubber were toxic.example is a-naphthylamineA carcinogen, which was frequently found as a

minor impurity (up to 50 ppm) in commercial aryl naphthylamines; notably, the widely used tyre antioxidant phenyl-P-naphthylamine, PBN.

ENVIRONMENTAL IMPACT OF POLYMER ADDITIVES

• very long induction period before overt signs of cancer began to appear.

ENVIRONMENTAL IMPACT OF POLYMER ADDITIVES

• the intermediate aldehydes and quinones formed from phenols (Scheme 3.10), are known to be potentially toxic to animals

ENVIRONMENTAL IMPACT OF POLYMER ADDITIVES

• Problem with pvc plasticiser

Health implications of DEHP Plasticiser

Reference

• Jan C.J. Bart. (2005). Additives in polymers : industrial analysis and application. DSM Research, The Netherlands : John Wiley & Sons Ltd.

• Scott Lambert. (2013). Environmental Risk of Polymers and their Degradation Products.University of York

• GERALD SCOTT. (1999). POLYMERS AND THE ENVIRONMENT. The Royal Society of Chemistry

Thank You