Soybean oil based copolymers containing silicon, boron or phosphorus: polymerization, characterization and fire retardance properties

Identificador:  TDX:818

Handle: https://hdl.handle.net/20.500.11797/TDX818

Autors:  Sacristán Benito, Marta

Resum:
Introducction <br/>The sustainable development concept came out of the United Nations Commision on Environment and Development in 1987 (Bruntland Commission) and it is defined as 'the development that meets the needs of the present without compromising the ability of future generations to meet their own needs'. From this point, both the society and the industry have considered what a sustainable development really means and the best ways to start to achieve it from their own standpoints. <br/>The principles of the United Nations Conference on environment and Development (UNCED) held in June 1992 in Rio de Janeiro, and Agenda 21, were formulated with the aim of preparing the world for the challenges of the 21st century. In this context, during the early 1990s the US Environmental Protection Agency (EPA) coined the phrase Green Chemistry 'To promote innovative chemical technologies that reduce or eliminate the use of generation of hazardous substances in the design, manufacture and use of chemical products'. The main challenges of Green Chemistry and Engineeiring can be summarized as: <br/>· utilizing renewable instead of scarce resources. <br/>· avoiding toxic/dangerous chemicals in safer processes to obtain safer products. <br/>· minimizing energy use. <br/>· minimizing waste and resource use, re-using products, recovering and recycling materials. So making processes globally more efficient. <br/><br/>Plant oils are one of the most widely applied renewable raw materials in the chemical industry for non-fuel applications. Vegetable oils are triglycerides (tri-esters of glycerol with long-chain fatty acids) with varying composition of fatty acids depending on the plant they are extracted from. Depending on the composition of plant oils, their Chemicals and physical properties are different.Vegetable oils are very used in polymer chemistry. Triglycerides have different reactive points through which we can obtain polymers from plant oils.There are two main approaches:The first one is the chemical modification of the triglycerides obtaining a large number of polymerizable monomers like expoxides or alcohols. The second approach is the direct polymerization of the carbon-carbon doubles bonds of plant oils through a free radical or a cationic mechanism.The free radical polymerization of double bonds has received less attention than cationic mechanism which has been very studied by Larock's group.In both cases thermosetting polymers with comparable properties to those of industrial can be obtained. Because of increasing use of synthetic polymeric materials during the lasts decades and the large fraction of the fire load in homes, it is necessary the use of fire retardants to reduce combustibility of the polymers, and smoke or toxic fume production. To get these requirements, the development of effective flame retardant materials is a key factor. To reduce the flammability, flame retardants can act in the gas phase or in condensed phase. In the gas phase fire retardants act as scavengers of the highly reactive radical species that propagate the combustion. In the condensed-phase fire retardants interfere in the thermal degradation processes modifying the reaction pathways and promoting the formation of char instead of volatile degradation products. Finally some flame retardants can act in both phases. <br/>Objectives <br/>The main objective of this Thesis was to develop new fire retardant biobased thermosets from vegetable oils as renewable resources. To achieve this goal it was carried out the cationic copolymerization of soybean oil, styrene and divinylbenzene with different silicon-or boron-or phosphorus containing comonomers.