A combined computational and experimental study on the polymerization of L-Lactide and e-Caprolactona

Orientador: Liliane Maria Ferrareso LonaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia QuímicaResumo: Polímeros biodegradáveis estão atraído grande interesse devido às suas propriedades biocompativeis e pelo baixo impacto ambiental. Entre esses diversos polímeros, podem-se destacar o PLA e a PCL, como dois polímeros de grande interesse industrial. Existem diferentes métodos de se produzir o PLA e a PCL sendo que nesse trabalho estudou-se a polimerização por abertura de anel dos seus respectivos monômeros. A cinética da polimerização desses monômeros por abertura de anel tem sido investigada por muitos pesquisadores em nível experimental, porém existem poucos trabalhos na literatura que focam na modelagem matemática de tais sistemas. Assim, o objetivo deste trabalho é o desenvolvimento de um modelo matemático e de um programa computacional para a simulação da polimerização por abertura de anel do L,L-lactídeo e da 'épsilon'-Caprolactona, usando como catalisador o octanoato de estanho (Sn(Oct)2) e como iniciadores o 1-dodecanol e a nanocelulose. Utilizou-se o método dos momentos para resolver as reações cinéticas e o balanço de massa da polimerização e um código computacional foi desenvolvido no software Matlab. Foi realizado um estudo dos parâmetros da reação e o impacto que cada um dos reagentes tem no resultado final da polimerização. Além disso todos os parâmetros foram validados com dados da literatura. Finalmente, após a comprovação da eficiência da simulação, foi testada a nanocelulose como iniciador. A nanocelulose apresentou taxas de conversão e massa molar mássica similares a do 1-dodecanol, sendo que a massa molar mássica ficou muito próxima da simulaçãoAbstract: Biodegradable polymers have attracted great interest because of their biocompatible properties and low environmental impact. Incoming polymers, such as PLA and PCL can be distinguished as two polymers with great industrial interest. There are different methods to produce PLA and PCL, but in this project it was investigated the ring opening polymerization of their respective monomers. The polymerization kinects have been investigated by many researchers at the experimental level, but there are few researches in the literature that focus on a mathematical modeling of such systems. Therefore, the objective of this work is the development of a mathematical model and a computational program for the opening polymerization of L,L-lactide and 'épsilon'-caprolactone, using tin octanoate (Sn(Oct)2) as a catalyst and 1-dodecanol and nanocellulose as hydroxyl sources. The method of moments was used to solve the polimerization kinects equations and the mass balance. A code in Matlab was developted to solve the equations and all parameters were confirmed using the literature. The impact of each reagent in the polimerization were evaluated as well as how the moisture affects the system. After validate the simulation, nanocellulose was used as the initiator. Nanocellulose had a similar conversion when compared with 1-dodecanol. Also, the molecular weight was very close to the simulationMestradoEngenharia QuímicaMestre em Engenharia Química2016/19847-1FAPES

Preparation and characterization of 3D-Printed biobased composites containing micro- or nanocrystalline cellulose

Stereolithography (SLA), one of the seven different 3D printing technologies, uses photosensitive resins to create high-resolution parts. Although SLA offers many advantages for medical applications, the lack of biocompatible and biobased resins limits its utilization. Thus, the development of new materials is essential. This work aims at designing, developing, and fully characterizing a bio-resin system (made of poly(ethylene glycol) diacrylate (PEGDA) and acrylated epoxidized soybean oil (AESO)), filled with micro- or nanocellulose crystals (MCC and CNC), suitable for 3D printing. The unfilled resin system containing 80 wt.% AESO was identified as the best resin mixture, having a biobased content of 68.8%, while ensuring viscosity values suitable for the 3D printing process (>1.5 Pa s). The printed samples showed a 93% swelling decrease in water, as well as increased tensile strength (4.4 ± 0.2 MPa) and elongation at break (25% ± 2.3%). Furthermore, the incorporation of MCC and CNC remarkably increased the tensile strength and Young’s modulus of the cured network, thus indicating a strong reinforcing effect exerted by the fillers. Lastly, the presence of the fillers did not affect the UV-light penetration, and the printed parts showed a high quality, thus proving their potential for precise applications

Photosensitive acrylates containing bio-based epoxy-acrylate soybean oil for 3D printing application

Stereolithography is a 3D-printing process that is rapidly shifting from being an expensive and limited technology to an affordable, precise, and fast method of mass production. However, most of the current resins are petroleum-based, which makes them toxic, non-degradable and with poor biocompatibility. In this study, a standard petroleum-based resin containing urethane acrylate and acrylic monomers was combined with epoxy-acrylate soybean oil (EASO), aiming to reduce its impact on the environment. Ratios varying from 10 to 50 wt% of EASO were incorporated into the commercial resin while maintaining the viscosity low, between 0.27 and 1.06 Pa s. The printed samples showed good quality and complete integration between the layers. The addition of 50 wt% of EASO increased the samples elongation at break by 108% (from 2.3% to 4.8%) and decreased the contact angle by 26.4% (from 72 to 53°). Moreover, the mixture showed good thermal and swelling stability and tensile strength in the range of other commercial cured systems. The addition of EASO may significantly contribute to the exploitation of greener materials, which well matches today's circular economy concept

A combined computational and experimental study on the polymerization of L-Lactide and ?-Caprolactona

Orientador: Liliane Maria Ferrareso LonaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia QuímicaResumo: Polímeros biodegradáveis estão atraído grande interesse devido às suas propriedades biocompativeis e pelo baixo impacto ambiental. Entre esses diversos polímeros, podem-se destacar o PLA e a PCL, como dois polímeros de grande interesse industrial. Existem diferentes métodos de se produzir o PLA e a PCL sendo que nesse trabalho estudou-se a polimerização por abertura de anel dos seus respectivos monômeros. A cinética da polimerização desses monômeros por abertura de anel tem sido investigada por muitos pesquisadores em nível experimental, porém existem poucos trabalhos na literatura que focam na modelagem matemática de tais sistemas. Assim, o objetivo deste trabalho é o desenvolvimento de um modelo matemático e de um programa computacional para a simulação da polimerização por abertura de anel do L,L-lactídeo e da "-Caprolactona, usando como catalisador o octanoato de estanho (Sn(Oct)2) e como iniciadores o 1-dodecanol e a nanocelulose. Utilizou-se o método dos momentos para resolver as reações cinéticas e o balanço de massa da polimerização e um código computacional foi desenvolvido no software Matlab. Foi realizado um estudo dos parâmetros da reação e o impacto que cada um dos reagentes tem no resultado final da polimerização. Além disso todos os parâmetros foram validados com dados da literatura. Finalmente, após a comprovação da eficiência da simulação, foi testada a nanocelulose como iniciador. A nanocelulose apresentou taxas de conversão e massa molar mássica similares a do 1-dodecanol, sendo que a massa molar mássica ficou muito próxima da simulaçãoAbstract: Biodegradable polymers have attracted great interest because of their biocompatible properties and low environmental impact. Incoming polymers, such as PLA and PCL can be distinguished as two polymers with great industrial interest. There are different methods to produce PLA and PCL, but in this project it was investigated the ring opening polymerization of their respective monomers. The polymerization kinects have been investigated by many researchers at the experimental level, but there are few researches in the literature that focus on a mathematical modeling of such systems. Therefore, the objective of this work is the development of a mathematical model and a computational program for the opening polymerization of L,L-lactide and "-caprolactone, using tin octanoate (Sn(Oct)2) as a catalyst and 1-dodecanol and nanocellulose as hydroxyl sources. The method of moments was used to solve the polimerization kinects equations and the mass balance. A code in Matlab was developted to solve the equations and all parameters were confirmed using the literature. The impact of each reagent in the polimerization were evaluated as well as how the moisture affects the system. After validate the simulation, nanocellulose was used as the initiator. Nanocellulose had a similar conversion when compared with 1-dodecanol. Also, the molecular weight was very close to the simulationMestradoEngenharia QuímicaMestre em Engenharia Química2016/19847-1FAPES

Preparation and characterization of a fully biobased resin system for 3d‑printing, suitable for replacing fossil‑based acrylates

The exploitation of plant-based monomers for additive manufacturing is a very promising approach to reduce the usage of petroleum-based plastics. In vat photopolymerization, acrylate epoxidized soybean oil (AESO) stands out as a versatile photocurable resin that can be modified and combined with other materials for multiple applications. In this work, different ratios of AESO were combined with isobornyl methacrylate (IBOMA), to develop a resin that exhibits similar mechanical properties to standard fossil-based resins. The photopolymerization reaction and conversion rate was monitored using FT-IR analysis, which showed conversions above 80%. Furthermore, curing tests revealed that the biobased resin needed less energy to cure when compared to commercial resins. The parts fabricated using the biobased resin also demonstrated enhanced tensile strength, tunable elongation at break and swelling resistance, which were comparable to standard fossil-based resins. This work demonstrates the potential of the proposed systems as a valuable alternative to traditional resins, paving the way for the development of high-performance materials for stereolithographic applications