662 research outputs found
Biobased thermosets from vegetable oils. Synthesis, characterization and properties
Biobased Thermosets from Vegetable Oils. Synthesis, Characterization, and PropertiesGerard Lligadas PuigEl desenvolupament sostenible va esdevenir com una de les idees claus del segle 20. S'entén per desenvolupament sostenible aquell tipus de desenvolupament que és capaç de satisfer les necessitats actuals sense comprometre els recursos i possibilitats de les futures generacions. Per assolir un desenvolupament sostenible és necessari promoure un desenvolupament social i econòmic pendent en tot moment del medi ambient. La conservació i la gestió dels residus és especialment important en aquest procés. La creixent demanda de productes derivats del petroli, juntament amb la disminució progressiva de les reserves de petroli són algunes de les moltes raons que han encoratjat la industria química a començar a utilitzar les fonts renovables com a matèria prima.En aquest context, en els darrers anys l'atenció s'ha centrat en la utilització de recursos anualment renovables, com són els recursos agrícoles, en la producció d'una gran varietat de productes industrials. Un dels recursos renovables més interessants per a la indústria química són els olis vegetals degut a la seva elevada disponibilitat i el seu ampli ventall d'aplicacions. Els olis vegetals formen part de la família de compostos químics coneguts com lípids, i estan constituïts majoritàriament per molècules de triglicèrids. Els triglicèrids estan formats per tres molècules d'àcid gras unides a una molècula de glicerol mitjançant enllaços ester. Els àcids grassos que es troben en la majoria d'olis vegetals estan constituïts per cadenes alifàtiques insaturades de entre 14 i 22 àtoms de carboni.La explotació industrial dels recursos naturals està actualment en el punt de mira de la comunitat científica. Concretament, el desenvolupament de materials polimèrics derivats de fonts renovables està rebent un interès creixent degut a la incertesa en el preu i les reserves de petroli. La substitució del petroli per productes derivats de fonts renovables és consistent amb el concepte de desenvolupament sostenible. El propòsit del treball portat a terme en aquesta tesi doctoral va ser desenvolupar nous materials termoestables utilitzant olis vegetals com a productes de partida. En el capítol 1 es discuteix la contribució de la química en el desenvolupament sostenible i es descriuen les possibilitats dels olis vegetals com a productes de partida en la síntesi de materials polimèrics. El capítol 2 descriu la preparació de dos noves famílies de materials híbrids orgànics-inorgànics derivats d'olis vegetals. Es descriu síntesi i caracterització de polímers híbrids derivats d'àcids grassos que contenen dobles enllaços carboni-carboni terminals utilitzant la reacció d'hidrosililació com a reacció d'entrecreuament, i la preparació de polímers derivats d'oli de llinosa epoxidat nanoreforçats amb silsesquioxans polièdrics. En el capítol 3 es descriu la síntesi d'un nou compost fosforat derivat de fonts renovables. Aquest compost s'ha utilitzat com a compost retardant a la flama reactiu en la preparació de resines epoxi derivades de fonts renovables amb propietats de resistència a la flama. La incorporació de fòsfor en resines epoxi d'aquest tipus ha donat lloc a polímers amb bones propietats de resistència a la flama. Finalment, en el capítol 4 es descriu la preparació d'una nova família de polièter poliols derivats d'oleat de metil epoxidat com a font renovable. Aquests poliols s'han utilitzat en la síntesi de poliuretans amb aplicacions específiques: poliuretans que incorporen silici amb propietats de resistència a la flama, i poliuretans segmentats amb aplicacions en biomedicina.Biobased Thermosets from Vegetable Oils. Synthesis, Characterization, and PropertiesGerard Lligadas PuigSustainable development, which became a key idea during the 20th century, may be regarded as the progressive and balanced achievement of sustained economic development, and improved social equity and environmental quality. Sustainable development comprises the three components of society, environment, and economy, and its goals can only be achieved if all three components can be satisfied simultaneously.The conservation and management of resources is especially important to this process. The growing demand for petroleum-based products and the resulting negative impact on the environment, plus the scarcity of non-renewable resources, are some of the many factors that have encouraged the chemical industry to begin using renewable resources as raw materials.This situation has led to considerable attention being focused recently on the use of annually renewable agricultural feedstock to produce a wide range of base chemicals and other industrial products. The renewable raw materials that are most important to the chemical industry are natural oils and fats because of their high availability and versatile applications. Vegetable oils constitute about 80% of the global oil and fat production, with 20% (and declining) being of animal origin. The use of these materials offers an alternative approach that is both sustainable and, with the right application, far more environmentally benign than fossil sources.Vegetable oils and fats form part of a large family of chemical compounds known as lipids. Vegetable oils are predominantly made up of triglyceride molecules, which have the three-armed star structure. Triglycerides comprise of three fatty acids joined at a glycerol junction. Most of the common oils contain fatty acids that vary from 14 to 22 carbons in length, with 0 to 3 double bonds per fatty acid.Research into the industrial exploitation of products derived from renewable resources is currently of immense international importance. In particular, the development of polymer materials from renewable resources is receiving considerable attention since the availability of crude oil will become severely restricted within the foreseeable future. The replacement of crude oil by renewable raw materials is also consistent with the aim of global sustainability.The purpose of the study reported in this thesis was to develop new biobased thermosetting polymers from vegetable oils as renewable resources. To achieve this goal, the experimental work focused on exploiting the reactivity of unsaturated fatty compounds. Chapter 1 discusses the contribution of chemistry to sustainable development, and also presents an overview of recent developments in the chemistry of vegetable oil-based polymers. Chapter 2 describes the preparation of two new types of organic-inorganic hybrid materials from vegetable oils. Hybrids with promising properties for optical applications were prepared by the hydrosilylation of alkenyl-terminated fatty acid derivatives with several hydrosilylating agents, and the first example of the preparation of biobased polyhedral oligomeric silsesquioxanes-nanocomposites from vegetable oil derivatives is reported. Chapter 3 describes the synthesis of a new phosphorus-containing fatty acid derivative. This compound is used as a reactive flame-retardant in the preparation of flame-retardant epoxy resins from terminal epoxy fatty acid derivatives. The incorporation of phosphorous into biobased epoxy resins yields polymers with good flame-retardant properties. Finally, chapter 4 describes the preparation of a new family of epoxidized methyl oleate based polyether polyols. These polyols are used in the synthesis of polyurethanes, some with specific applications: silicon-containing polyurethanes with enhanced flame-retardant properties, and polyurethane networks with potential applications in biomedicine
Velocity based controllers for dynamic character animation
Dynamic character animation is a technique
used to create character movements based on
physics laws. Proportional derivative (PD)
controllers are one of the preferred techniques
in real time character simulations for driving
the state of the character from its current state
to a new target-state. In this paper is presented
an alternative approach named velocity
based controllers that are able to introduce
into the dynamical system desired limbs relative
velocities as constraints. As a result, the
presented technique takes into account all the
dynamical system to calculate the forces that
transform our character from its current state
to the target-state. This technique allows realtime
simulation, uses a straightforward parameterization
for the character muscle force capabilities
and it is robust to disturbances. The
paper shows the controllers capabilities for the
case of human gait animation.Postprint (published version
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SET-LRP in biphasic mixtures of fluorinated alcohols with water
Biphasic-binary mixtures of 2,2,2-trifluoroethanol (TFE) or 2,2,3,3-tetrafluoropropanol (TFP) with water were used as reaction media to synthesize well-defined poly(methyl acrylate) (PMA) with chain end functionality close to 100% by SET-LRP. Non-activated Cu(0) wire was used as a catalyst, taking advantage of the Cu(0)-activation property that these fluorinated alcohols possess. Biphasic-binary mixtures of water, containing a ligand and Cu(II)Br2 either generated by disproportionation of Cu(I)Br or externally added, and an organic solvent, containing a monomer and a polymer, were studied. Two N-ligands were investigated: the classic tris(2-dimethylaminoethyl)amine (Me6-TREN) and tris(2-aminoethyl)amine (TREN), as a more economically attractive alternative for technological purposes. The results reported here support the replacement of Me6-TREN by TREN, taking into account the fact that the latter requires small loadings of an externally added Cu(II)Br2 deactivator and a ligand in the water phase to mediate a living radical polymerization process. Both catalytic systems ensure efficient SET-LRP processes with first order kinetics to high conversion, linear dependence of experimental Mn on conversion, narrow molecular weight distribution, and near-quantitative chain end functionality
Automatic adjustment of rigs to extracted skeletons
In the animation, the process of rigging a character is an
elaborated and time consuming task. The rig is developed for a specific
character, and it can not be reused in other meshes. In this paper we
present a method to automatically adjust a human-like character rig to
an arbitrary human-like 3D mesh, using a extracted skeleton obtained
from the input mesh. Our method is based on the selection and extraction
of feature points, to find an equivalence between an extracted skeleton
and the animation rig.Peer ReviewedPostprint (published version
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A green solvent-to-polymer upgrading approach to water-soluble LCST poly(N-substituted lactamide acrylate)s
We report a green solvent-to-polymer upgrading transformation of chemicals of the lactic acid portfolio into water-soluble lower critical solution temperature (LCST)-type acrylic polymers. Aqueous Cu(0)-mediated living radical polymerization (SET-LRP) was utilized for the rapid synthesis of N-substituted lactamide-type homo and random acrylic copolymers under mild conditions. A particularly unique aspect of this work is that the water-soluble monomers and the SET-LRP initiator used to produce the corresponding polymers were synthesized from biorenewable and non-toxic solvents, namely natural ethyl lactate and BASF's Agnique (R) AMD 3L (N,N-dimethyl lactamide, DML). The pre-disproportionation of Cu(I) Br in the presence of tris[2-(dimethylamino)ethyl]amine (Me6TREN) in water generated nascent Cu(0) and Cu(II) complexes that facilitated the fast polymerization of N-tetrahydrofurfuryl lactamide and N,N-dimethyl lactamide acrylate monomers (THFLA and DMLA, respectively) up to near-quantitative conversion with excellent control over molecular weight (5000 < M-n < 83 000) and dispersity (1.05 < D < 1.16). Interestingly, poly(THFLA) showed a degree of polymerization and concentration dependent LCST behavior, which can be fine-tuned (T-cp = 12-62 degrees C) through random copolymerization with the more hydrophilic DMLA monomer. Finally, covalent cross-linking of these polymers resulted in a new family of thermo-responsive hydrogels with excellent biocompatibility and tunable swelling and LCST transition. These illustrate the versatility of these neoteric green polymers in the preparation of smart and biocompatible soft materials
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A green solvent-to-polymer upgrading approach to water-soluble LCST poly(N-substituted lactamide acrylate)s
We report a green solvent-to-polymer upgrading transformation of chemicals of the lactic acid portfolio into water-soluble lower critical solution temperature (LCST)-type acrylic polymers. Aqueous Cu(0)-mediated living radical polymerization (SET-LRP) was utilized for the rapid synthesis of N-substituted lactamide-type homo and random acrylic copolymers under mild conditions. A particularly unique aspect of this work is that the water-soluble monomers and the SET-LRP initiator used to produce the corresponding polymers were synthesized from biorenewable and non-toxic solvents, namely natural ethyl lactate and BASF's Agnique® AMD 3L (N,N-dimethyl lactamide, DML). The pre-disproportionation of Cu(I)Br in the presence of tris[2-(dimethylamino)ethyl]amine (Me6TREN) in water generated nascent Cu(0) and Cu(II) complexes that facilitated the fast polymerization of N-tetrahydrofurfuryl lactamide and N,N-dimethyl lactamide acrylate monomers (THFLA and DMLA, respectively) up to near-quantitative conversion with excellent control over molecular weight (5000 < Mn < 83 000) and dispersity (1.05 < Đ < 1.16). Interestingly, poly(THFLA) showed a degree of polymerization and concentration dependent LCST behavior, which can be fine-tuned (Tcp = 12–62 °C) through random copolymerization with the more hydrophilic DMLA monomer. Finally, covalent cross-linking of these polymers resulted in a new family of thermo-responsive hydrogels with excellent biocompatibility and tunable swelling and LCST transition. These illustrate the versatility of these neoteric green polymers in the preparation of smart and biocompatible soft materials
Polyacrylates Derived from Biobased Ethyl Lactate Solvent via SET-LRP
The precise synthesis of polymers derived from alkyl lactate ester acrylates is reported for the first time. Kinetic experiments were conducted to demonstrate that Cu(0) wire-catalyzed single electron transfer-living radical polymerization (SET-LRP) in alcohols at 25 °C provides a green methodology for the LRP of this forgotten class of biobased monomers. The acrylic derivative of ethyl lactate (EL) solvent and homologous structures with methyl and n-butyl ester were polymerized with excellent control over molecular weight, molecular weight distribution, and chain-end functionality. Kinetics plots in conventional alcohols such as ethanol and methanol were first order in the monomer, with molecular weight increasing linearly with conversion. However, aqueous EL mixtures were found to be more suitable than pure EL to mediate the SET-LRP process. The near-quantitative monomer conversion and high bromine chain-end functionality, demonstrated by matrix-assisted laser desorption ionization time-of-flight analysis, further allowed the preparation of innovative biobased block copolymers containing rubbery poly(ethyl lactate acrylate) poly(ELA) sequences. For instance, the poly(ELA)-b-poly(glycerol acrylate) block copolymer self-assembled in water to form stable micelles with chiral lactic acid-derived block-forming micellar core as confirmed by the pyrene-probe-based fluorescence technique. Dynamic light scattering and transmission electron microscopy measurements revealed the nanosize spherical morphology for these biobased aggregates
Fundamentals of mass transfer and kinetics for biosorption of oil and grease from agro-food industrial effluent by Serratia marcescens SA30
Fundamental studies of mass transfer and kinetics are essential for a detailed understanding of the characteristics and the mechanisms of biosorptions. In this study, the modified mass transfer factor models were used to assess the rates of global, external and internal mass transfer for the biosorption of oil and grease (O&G) from agro-food industrial effluent (AFIE) by Serratia marcescens SA30. Using a packed-bed column reactor to run the experiments at different O&G concentrations, this study finds that the global mass transfer rate increases exponentially accompanied with the sudden increase of the cell surface sorption. The influence of concentration on the external mass transfer is very remarkable due to the effects of driving force and biomass growth can lead to a rapid movement of O&G molecules from the bulk water to extracellular precipitation. The resistance to mass transfer could be dependent on intracellular accumulation at the beginning and then on film mass transfer at the final stage of biosorption of O&G by Serratia marcescens SA30. This study would provide a green and sustainable pathway for removing O&G from AFIE
The effect of maleinized linseed oil as biobased plasticizer in poly (lactic acid)-based formulations
[EN] The use of maleinized linseed oil (MLO) as a potential biobased plasticizer for poly(lactic acid) (PLA) industrial formulations with improved toughness was evaluated. MLO content varied in the range 0-20 phr (parts by weight of MLO per hundred parts by weight of PLA). Mechanical, thermal and morphological characterizations were used to assess the potential of MLO as an environmentally friendly plasticizer for PLA formulations. Dynamic mechanical thermal analysis and differential scanning calorimetry revealed anoticeable decrease in the glass transition temperature of about 6.5 degrees C compared to neat PLA. In addition, the cold crystallization process was favoured with MLO content due to the increased chain mobility that the plasticizer provides. PLA toughness was markedly improved in formulations with 5 phr MLO, while maximum elongation at break was obtained for PLA formulations plasticized with MLO content in the range 15-20 phr. Scanning electron microscopy revealed evidence of plastic deformation. Nevertheless, phase separation was detected in plasticized PLA formulations with high MLO content (above 15-20 phr MLO), which had a negative effect on overall toughness. (C) 2017 Society of Chemical IndustryThis research was funded by the Ministry of Economy and Competitiveness - MINECO, ref. MAT2014-59242-C2-1-R. The authors also thank Conselleria d'Educacio, Cultura i Esport - Generalitat Valenciana, ref. GV/2014/008, for financial support. DG-G thanks the Spanish Ministry of Education, Culture and Sports for financial support through an FPU grant (FPU13/06011).Ferri, J.; Garcia-Garcia, D.; Montanes, N.; Fenollar, O.; Balart, R. (2017). The effect of maleinized linseed oil as biobased plasticizer in poly (lactic acid)-based formulations. Polymer International. 66(6):882-891. https://doi.org/10.1002/pi.5329S88289166
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