Sythesis and characterization of biodegradable grafted copolymers

This work aimed to prepare biodegradable copolymers based on ethylene vinyl acetate and polylactic acid using transesterification reactions. The materials were prepared in the melt and then characterized by elemental analysis, infrared spectroscopy, X-ray, scanning electron microscopy, gel permeation chromatography and rheology. Selective extractions for all samples were made, and the results indicate that a maximum of 25% of EVA-g-PLA copolymer was synthesized by this method. Biodegradation tests were carried out using the standard ISO 14851 (1999), which specifies a method for determining the biochemical oxygen demand in a closed respirometer. The results demonstrate that the procedure used allowed the synthesizes of biodegradable copolymers with mechanical properties similar to conventional polymers

Influence of EVA molar mass on preparation of EVA-g-PCL biobased copolymers

The rapid growth of plastic production is considered as a serious source of environment pollution. Approximately 100 million tons of plastics are produced each year and within a short period of time almost half are disposed to the environment. A way to overcome this problem would be the use of biodegradable polymers. Several attempts are made to replace synthetic polymers by biodegradable ones. Nevertheless, they did not prove yet to be useful for commercial applications due to their high price or limitations in terms of thermal and mechanical properties. Alternative to biodegradable polymers are biobased polymers, which can be prepared by blending or copolymer formation of a biodegradable and a synthetic polymer. Thus, the present work aims to prepare copolymers of ethyl vinyl acetate (EVA) and poly(ξ-caprolactone) (PCL), EVA-g-PCL, and to study the influence of the molar mass of EVA on copolymer formation and its properties. The materials were prepared in a internal batch mixer using titanium propoxide (Ti(OPr)4) as catalyst. Characterization was performed by selective extraction of the formed copolymers, SEM, FTIR, rheology, DSC, TGA and tensile properties. Morphological results by SEM evidence copolymer formation, the particle size of the dispersed phase decreases as the EVA molar mass decreases. The tensile properties of the prepared materials are similar to the ones of synthetic polymers. The biodegradability, evaluated based on biochemical oxygen demand method, showed that biodegradability increases as the EVA molar mass increases.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/29802/200

Synthesis of biodegradable copolymers

This work aimed to prepare biodegradable copolymers based on ethylene vinyl acetate and polylactic acid using transesterification reactions. The materials were characterized by elemental analysis, infrared spectroscopy, rheology, scanning electron microscopy and gel permeation chromatography. Selective extractions for all samples were made, and the results indicate that a maximum of 25% of EVA-g-PLA copolymer was synthesized by this method. Biodegradation tests were carried out using the standard ISO 14851 (1999) which specifies a method for determining the biochemical oxygen demand in a closed respirometer. This procedure allowed the synthesizes biodegradable copolymers with mechanical properties similar to conventional materials

Synthesis of biodegradable copolymers based on ethylene vinyl acetate and polylactic acid

In the present study biodegradable copolymers of ethylene vinyl acetate and polylactic acid were synthesized using transesterification reactions, the structure, morphology, mechanical properties and biodegradability of the produced materials were characterized. Ethylene vinyl acetate was modified with polylactic acid in an internal mixer using titanium propoxide as transesterification catalyst. The graft copolymers were characterized by elemental analysis, infrared spectroscopy, rheology, scanning electron microscopy and thermal analysis. Selective extractions for all copolymers were made, and the results indicate that a maximum of 25 % of EVA-g-PLA copolymer was synthesized by this method. Biodegradation tests were carried out using the standard ISO 14851 (1999), which specifies a method for determining the biochemical oxygen demand in a closed respirometer. This procedure allowed to synthesize biodegradable copolymers with mechanical properties similar to conventional polymers

Effect of PCL and EVA molar mass on the development of sustainable polymers

Biodegradable grafted copolymers, EVA-g-PCL, have been synthesized by reactive extrusion, through transesterification reaction between ethylene-vinyl acetate copolymer (EVA) and poly(ε-caprolactone) (PCL) using titanium propoxide (Ti(OPr)4) as catalyst. The effect of EVA and PCL molar mass on the amount of grafted copolymer and materials properties was investigated. The prepared blends were characterized by several analytical techniques, such as, selective extractions, rheology, TGA, DSC, SEM, mechanical properties, and the biodegradability was evaluated based on biochemical oxygen demand method. The results showed that the amount of copolymer increases as the amount of catalyst increases. Moreover, using EVA and PCL with high and low molar mass, respectively, allowed to obtain a material exhibiting properties similar to conventional polymers and higher biodegradability.The authors acknowledge the financial support given by FCT through the project PTDC/AMB/73854/2006 and the PhD grant SFRH/BD/29802/2006

Grafting of PCL to EVA by reactive processing: effect of PCL molar mass

Biobased graft copolymers, EVA-g-PCL, has been synthesized by transesterification reaction between EVA and PCL, using titanium propoxide Ti(OPr)4 as catalyser. The extent of the grafting reaction was estimated from the amount of copolymer extracted. Characterization of the copolymer formation was also performed using several analytical techniques, such as, SEM, TGA, DSC and XPS. Oxygen measurements were carried out to monitor the biodegradability of the prepared materials. The results obtained showed this method is an efficient way to enhance EVA biodegradability.Fundação para a Ciência e a Tecnologia (FCT

Biobased grafted polyesters prepared by in situ ring-opening polymerization

EVA-g-PLA and EVA-g-PCL copolymers were synthesized by in situ polymerization of e-caprolactone and lactide, in the presence of molten ethylene vinyl acetate (EVA) copolymer, using titanium phenoxide (Ti(OPh)4) as initiator. The materials prepared in a internal batch mixer were characterized by 1H NMR, SEM, FTIR, rheology, DSC, TGA and SEC and the synthesized copolymers identified through selective extraction. The mechanical performance was characterized by tensile tests and the biodegradability by the biochemical oxygen demand method. The results indicated that approximately 11 wt.% of EVA-g- PCL and 8 wt.% of EVA-g-PLA copolymers were synthesized. Moreover, the increase of the Young modulus was higher for the sample containing EVA-g-PCL. This sample also exhibited the higher biodegradability (36%).Fundação para a Ciência e a Tecnologia (FCT)

Synthesis of EVA-g-PLA copolymers using transesterification reactions

The synthesis of EVA-g-PLA grafted copolymers was carried out by reactive extrusion, through transesterification reaction between ethylene vinyl acetate copolymer (EVA) and polylactide (PLA), using titanium propoxide (Ti(OPr)4) and titanium phenoxide (Ti(OPh)4) as catalysts. Different materials were prepared by changing the relative amount of polylactide and catalyst. The extent of the grafting reaction, which depends on the quantity of polylactide and catalysts, was estimated by selective extractions. The influence of the same parameters on the final structure, morphology and thermal and mechanical properties was also evaluated. The results showed that Ti(OPr)4 exhibited higher efficiency as a catalyst than Ti(OPh)4. Moreover, using the former catalyst, 25 wt.% of EVA-g-PLA copolymer was synthesized. The sample containing the higher amount of copolymer exhibits the better properties and the higher biodegradability.The authors acknowledge the financial support given by FCT through the project PTDC/AMB/73854/2006 and the PhD grant SFRH/BD/29802/2006

Synthesis of fatty ether-esters and polyesters for EPDM plasticization

International @ CDFA+GSCInternational audienceIntroductionThe use of renewable resources in the elaboration of various industrial materials and chemicals has been recently revitalized because of environmental concerns. Nowadays, vegetable oils constitute one of the most important classes of renewable resources. They can be extracted from the soybean or rapeseed press cakes. They are already a part of some polymeric material formulations but can also be used as polymer plasticizers To substitute paraffinic oil that are used at present as plasticizers for EPDM, modified vegetables oils were prepared as a new bio plasticizer. Efficient oxirane ring opening of fatty epoxides was performed to synthesis various poly ester and ether-ester. Some physico-chemical characterization of the synthetized modified oils were reported [ref]CC. In this paper, we wish to present our contribution in the synthesis of this bioplasticizers together with some characterizations in EPDM formulation. Results and discussionWe prepared a range of products via successive ring oxirane opening reaction. The ether-ester modified vegetable oils were prepared in two steps from epoxide derivatives. Initially, the ring opening of the epoxide with an alcohol was carried out to yield the hydroxyl-ether intermediate which was esterified in the presence of an anhydride. The polyester derivatives were prepared from the fatty epoxide via opening reaction with a series of acids then esterification of the resulting alcohol with anhydride. The reaction was performed in solvent free conditions and the influence of the catalysts (homogeneous or heterogeneous) in these reactions was evaluated. With this approach ether-ester and poly esters were prepared. Homogeneous (strong acid, Lewis acid [1, 2]) or heterogeneous catalysts (Amberlyst 15 [3]) were compared in solvent free conditions and with an excess of alcohol. With this approach fatty ether-esters were prepared. Among the evaluated catalysts, Amberlyst 15 and BF3.OEt2 exhibited significant activities for the two steps. Optimisations of the reaction conditions were performed in order to achieve complete conversion. The products were characterized by NMR, GC, GPC and TGA. Thermal stability plays a key role for EPDM plasticization (figure 1). Their properties as EPDM bioplasticizer are compared to non-modified oil and fatty polyester. Cyrille GraphFig. 2: Rheology analysis of modified and non modified oil.Some vegetable oils derivatives may be good candidates to substitute paraffinic oils usually added as plasticizer . The influence of the chemical modifications on the properties will be described.ConclusionThis two-step ring opening approach allowed to prepare a range of potential bioplasticizers for EPDM starting from vegetable oils. This is an interesting method to add new functions on fatty acid esters and to have low polarity with different functions. References1.Soi, H.S., et al., Monomers of polyhydroxy compounds and manufacturing methods therefor, CN1962601A, 2007.2.Hwang, H.-S. and Erhan, S.Z., Industrial Crops and Products, 2006. 23, 3: 311-317.3.Cramail, H., et al., Manufacture of polyols having ester groups from vegetable oils for manufacture of polyurethanes, FR2950051A1, 2011

Procédé de préparation d’un matériau composite échangeur d’ions comprenant une matrice polymère et une charge consistant en des particules échangeuses d’ions

L'objectif de ce brevet consiste à réaliser une membrane de pile a combustible sans avoir recours au procédé "casting" qui nécessite un solvant. Ce procédé d’extrusion réactive permet de former une charge inorganique pendant la mise en œuvre de la matrice polymere en présence d’un agent comptabilisant à base de copolymère synthétisé par copolymérisation radicalaire du fluorure de vinylidène avec un autre comonomère fonctionnelL'application visée de ces matériaux concerne le domaine de l’énergie (matériaux pour piles à combustible PEMFC ou DMFC, AFC, les matériaux pour batterie Lithium-ion). ainsi que le domaine de l’environnement tel que les purificateurs d’ions ou de matériaux électrochromes (efficacité énergétique)