Functional High Performance Polybenzoxazines And Their Properties

Tez (Doktora) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2016Thesis (Ph.D.) -- İstanbul Technical University, Institute of Science and Technology, 2016Fenolik reçineler, yaygın uygulamaları sebebi ile yapıştırıcı sanayii’nde, havacılık yapı uygulamalarında, baskı devre kartlarında, iletken polimer yapılarda, malzeme kapsülleri ve elektronik olmak üzere çok çeşitli alanlarda kullanılmaktadır. Fenolik reçineler, akrilatlar, bismaleimidler, poliesterler, epoksi reçineler ve izosiyanat polimerler termosetlerin en iyi bilinen üyeleridir. Yüksek işlem sıcaklıkları ve kürleme sırasında gözenek oluşumu, bu malzemelerin aşılması gereken başlıca zorluklarıdır. Son zamanlarda, benzoksazin bazlı fenolik reçineler geliştirilmiş ve fenolik reçinelerin yeni bir türü olarak önemli derecede dikkat çekmiştir. Polibenzoksazinler; iyi bir ısıl kararlılık, yüksek camsı geçiş sıcaklığı, yüksek yanma ürünü, kürleme için katalizöre gerek olmaması, kürleme sırasında hacmi değişmemesi, düşük nem absorpsiyonu ve herhangi bir uçucu açığa çıkarmaması gibi üstün özelliklere sahiptir. Son zamanlarda, benzoksazin monomerlerinin ve polimerik benzoksazin öncüllerinin tasarım esnekliği sayesinde, yenilikçi yaklaşımlar kullanılarak, kendi kendine iyileşebilen, elektrokimyasal olarak aktif hale gelebilen akıllı kaplamalar, ağır metaller için akıllı sorbentler, hidrofobik yüzeyler ve gözenekli polibenzoksazinler gibi çeşitli akıllı malzemeler elde edilmiştir. Bu stratejilerin önemli ve polibenzoksazinlerin benzersiz özellikleri ve avantajlarını dikkate alarak, bu tezde, çeşitli fonksiyonel grupların benzoksazin öncülleri ile kombinasyonu ve elde edilen ürünün özelliklerinin araştırılması üzerinde duruldu. Tezin ilk bölümünde, poli(propilen oksit) içeren benzoksazin unitelerinin supramoleküler etkileşim sonucu kendi kendine iyileşebilmesini sağlayan yeni bir moleküler tasarım geliştirildi. 2000 Da moleküler ağırlığına sahip poli(propilen oksit) bisamin (PPO), 12360 Da moleküler ağırlığına sahip PPO-Benz vermek üzere formaldehit ve bisfenol A ile reaksiyona sokuldu. Şekil 4 : Karboksilik asit içeren benzoksazin monomeri ve PPO-Benz karışımından kendi kendine iyileşebilen film eldesi. Çapraz-bağlanmış polimer filmler, uygun kompozisyonlarda PPO-Benz ve karboksilik asit içeren benzoksazin monomerlerinin (Carb-Benz), kloroformda çözülerek hazırlanmasıyla, çözücü uçurularak ve 200 °C de benzoksazin gruplarının halka açılma reaksiyonu sonucunda elde edildi. Film ve son ürünün ısısal kürleme ve ısısal kararlılığı incelendi. Bu filmlerin kendini iyileştirme kapasitesinin, formülasyonun içinde Carb-Benz kullanıldığı zaman arttığı gösterildi. Tezin ikinci bölümünde, yeni bir yaklaşım kullanılarak, alkil fonksiyonel benzoksazin (BA-ala) ve elementel kükürt reaksiyona sokularak, kükürtçe zengin polibenzoksazin kopolimerler elde edildi. Eşzamanlı inverse vulkanizasyon ve benzoksazinlerin halka açma reaksiyonu, belirli oranlarda çözünür kopolimerler oluşturdu. Monomer yapısı ve polimerizasyonda kullanılan oranlar gibi parametreler incelendi. Kopolimerlerin ısısal kararlılığı araştırıldı, termogravimetrik analiz (TGA) ve diferansiyel tarama kalorimetrisi (DSC) kullanılarak saf BA-ala ile türetilen polibenzoksazinle kıyaslandı. Taramalı elektron mikroskobu (SEM) ile malzemelerin yüzey özellikleri incelendi ve elementel kükürt ve benzoksazin kopolimerlerinin mikrometre düzeyinde faz ayrılması olmadan üretilebilirliği doğrulandı. Ayrıca, sünger tipi makro-gözenekli çözünmez polibenzoksazin ağları, 20% kükürt oranında elde edildi. Şekil 5 : Alkil fonksiyonel benzoksazin (BA-ala) ve elementel kükürtün reaksiyonuyla, kükürtçe zengin polibenzoksazin kopolimerlerin eldesi için yeni bir strateji. Son olarak, yan zinciri benzoksazin fonksiyonel polibütadienler, fotokimyasal hidrojen ayırma yöntemi ile elde edildi. İlk olarak, yapısında kromoforik karbonil ve hidrojen verici kısımları olan ışığa duyarlı benzoksazin bileşikleri, vanilin veya 4-hidroksibenzofenon kullanılarak geleneksel benzoksazin sentez metoduyla elde edildi. Katkısız polibutadien (PB), benzofenon benzoksazin (BPH ptol) ve vanilin benzoksazin (Van-A) varlığında, 300-350 nm ışık altında aydınlatılarak, zinciri başına yaklaşık 4-5 benzoksazin ünitesi içeren PB oluşturdu. Başarılı modifikasyon, spektral ve ısısal incelemeler ile teyit edildi. Benzoksazin bağlı PB’lerin, herhangi bir katalizör gerektirmeden, termal kürleme ve yüksek yanma verimi ile polibütadien termosetler oluşturduğu gösterildi. Şekil 6 : Yapısında kromoforik karbonil ve hidrojen verici bölümleri olan ışığa duyarlı benzoksazin bileşiği.Phenolic resins are leading the polymer market due to their widespread applications such as adhesives, structural applications materials in aerospace, printed circuit boards, conductive polymer elements, and encapsulation materials for electronic applications. Phenolic resins, acrylates, bismaleimides, polyesters, epoxy resins and isocyanate polymers are the best known members of the thermosets. High processing temperatures and void formation during curing are the main challenges must be overcome regarding application of these materials. Lately, benzoxazine based phenolic resins has been developed and attracted significant attention as a novel type of phenolic resin. Polybenzoxazines have various outstanding properties, including good thermal stability, high glass transition temperature, high char yield, no need of catalysts for curing, near-zero volume changes during curing, low moisture absorption and no volatile release. Recently, owing to the design flexibility of benzoxazine and related polymeric benzoxazine precursors, various smart materials were synthesized by innovative strategies including self-healing materials, electrochemically activated smart coatings, smart sorbents for heavy metals, hydrophobic surface applications and porous polybenzoxazine resins. Taking account of the unique advantages of these strategies and attractive characteristics of polybenzoxazines, in this thesis, we focused on the combination of various functional groups with benzoxazine precursors and then investigated the resulted products properties. In the first part of the thesis, a self-healing strategy for poly(propylene oxide)s bearing benzoxazine units (PPO-Benz) through supramolecular attractions is described. Poly(propylene oxide) bisamine (PPO) with a molecular wieght of 2000 Da were reacted with formaldehyde and bisphenol A to yield desired PPO-Benz with 12360 Da. The cross-linked polymer films were then prepared by solvent casting of suitable compositions of PPO-Benz and carboxlic acid containing benzoxazine monomer (Carb-Benz) in chloroform followed by thermal ring opening reaction of benzoxazine groups at 200 °C. Thermal curing and thermal stability of the film and final products were investigated. It was demonstrated that the self-healing capacity of the films were improved by employing Carb-Benz in the formulation. Figure 1 : Self-healable film preparation from carboxylic acid containing benzoxazine monomer and PPO-Benz. In the second part of the thesis, a novel strategy to obtain sulfur rich polybenzoxazine copolymers by reacting allyl functional benzoxazine (BA-ala) and elemental sulfur was described. Simultaneous inverse vulcanization and ring-opening reactions of benzoxazine generated soluble copolymers in specific feed ratios. Parameters such as monomer structure and feed ratios on the polymerization were studied. The thermal stability of the copolymers was investigated and compared to that of polybenzoxazines derived from neat BA-ala by using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The surface properties of the materials as examined by scanning electron microscope (SEM) confirmed that elemental sulfur and benzoxazine copolymers can be produced without a phase separation at micrometer level. Moreover, a sponge like insoluble macroporous polybenzoxazine networks was obtained at the 20%-wt feed ratio of sulfur. Figure 2 : A novel strategy to obtain sulfur rich polybenzoxazine copolymers by reacting allyl functional benzoxazine (BA-ala) and elemental sulfur. Finally, side-chain benzoxazine functional polybutadienes was synthesized by photoinduced hydrogen abstraction process. First, photosensitive benzoxazine compounds possessing both chromophoric carbonyl and hydrogen donating sites in the structure were synthesized using vanillin or 4-hydroxybenzophenone in the conventional benzoxazine synthesis. Irradiation of neat polybutadiene (PB) in the presence of the corresponding benzoxazines, namely benzophenone benzoxazine (BPh-ptol) and vanillin benzoxazine (Van-a) under 300–350 nm light gave PBs with approximately 4-5 benzoxazine units per chain. Successful modification was confirmed by the spectral and thermal investigations. It is shown that benzoxazine modified PBs undergo thermally activated curing in the absence of any catalyst forming polybutadiene thermoset with high char yield. Figure 3 : Photoactive benzoxazines having both chromophoric carbonyl and hydrogen donating sites were synthesized using vanillin or 4-hydroxybenzophenone by conventional benzoxazine synthesis methodology.DoktoraPh.D

Development of novel formulations based on biopolymers

Biopolymers, generally prepared from renewable sources, have attracted increasing attention due to their unique properties, such as nontoxicity, biodegradability and biocompatibility. Indeed, the above materials have been widely applied in the biomedical field, in the development of electronic devices as well as in the food packaging. Two of the most extensively studied and exploited biopolymers are poly(lactic acid) (PLA) and polycaprolactone (PCL), which have been the objects of the present work. Despite the significant interest in these polymers, for large-scale exploitation of both PLA and PCL, it is necessary to take into account some specific issues concerning their properties. In this regards, it is relevant to underline that the methods, which can be applied for improving their characteristics or those used for disclosing new features, have to take into account the economic impact and the "bio" nature of the material, which should be maintained in the final formulation. In particular, in the case of PLA, one of the major issues, which reduces its exploitation in durable applications, is its low hydrolytic stability, compared with other similar materials. Moreover, in the applications requiring high gas barrier, the use of PLA is critical and needs a further reduction of its gas permeability. Furthermore, concerning exploitations, where electrical and thermal conductivity is demanded, the insulating nature of the above biopolymers, requires the applications of proper conductive fillers. As such, the main aim of the thesis work main has been the improvement of the two biopolymer properties, developing novel formulations, whose design has taken into account all the mentioned issues. In the case of PLA, the barrier properties, the resistance to hydrolytic degradation as well as the antistatic features have been improved by modifying the material surface by means of the application of methods based on the chemical grafting or the Layer by Layer deposition and on the use of proper fillers, such as Polyhedral Oligomeric Silsesquioxane (POSS) and graphene oxide (GO). In addition, formulations capable of imparting thermal and electrical conduction to both PLA and PCL have been studied, combining the two biopolymers with graphite nanoplatelets (GNP)

Mesoporous Silica-Based Materials for Electronics-Oriented Applications

International audienceElectronics, and nanoelectronics in particular, represent one of the most promising branches of technology. The search for novel and more efficient materials seems to be natural here. Thus far, silicon-based devices have been monopolizing this domain. Indeed, it is justified since it allows for significant miniaturization of electronic elements by their densification in integrated circuits. Nevertheless, silicon has some restrictions. Since this material is applied in the bulk form, the miniaturization limit seems to be already reached. Moreover, smaller silicon-based elements (mainly processors) need much more energy and generate significantly more heat than their larger counterparts. In our opinion, the future belongs to nanostructured materials where a proper structure is obtained by means of bottom-up nanotechnology. A great example of a material utilizing nanostructuring is mesoporous silica, which, due to its outstanding properties, can find numerous applications in electronic devices. This focused review is devoted to the application of porous silica-based materials in electronics. We guide the reader through the development and most crucial findings of porous silica from its first synthesis in 1992 to the present. The article describes constant struggle of researchers to find better solutions to supercapacitors, lower the k value or redox-active hybrids while maintaining robust mechanical properties. Finally, the last section refers to ultra-modern applications of silica such as molecular artificial neural networks or super-dense magnetic memory storage

Improved Thermal and Mechanical Properties and Increased Miscibility of Polybenzoxazine in Blends with Functionalized Thermoplastics and Particles

The solubility, polymerization, and the macromolecular characterization of cured blends of BPA-based benzoxazine (BA-a) in end group tosylated poly(ethylene glycol) (mPEGOTs), polysulfone (PSUOTs), and poly(D,L-lactic acid) (PDLLAOTs) are studied and compared to their hydroxyl terminated analogues. The cure temperature for BA-a blends with tosylated polymers was reduced by ~60 °C compared to that of the pure BA-a. This confirms that the tosylated polymer is an accelerant for BA-a ring opening polymerization (ROP). There are two proposed mechanism for the production of free tosylate and cationic BA-a based initiators as a cure catalyst for BA-a ROP – where the former was detected by TGA-FTIR and TGA-MS. SEM confirmed a grafted polymer network from BA-a and mPEGOTs, P(BA-a)-graft-mPEGOTs, this homogenous microstructure was also found in PBA-a/PSUOTs blends. The glass transition temperature and the thermal stability of the P(BA-a)-graft-mPEGOTs can be tuned based on the composition of the BA-a/mPEGOTs resin. The potential applications of such grafted polymers may lead to novel materials for the biomedical plastics, electronics, membranes, and aerospace industries. Further blends were prepared with microparticles of silica (SiOH) and the tosylate- (SiOTs) and phenyl- (SiPh) functionalized analogues. Increased modulus of PBA-a was found in all silica blends, the reduction in cure temperature was found only in blends of BA-a and SiOTs. By SEM, PBA-a/SiOTs blends were determined to have a unique morphology. Three benzoxazine-based surfactants were synthesized from the coupling of p-hydroxy methylbenzoxazine with mPEGOTs. All three surfactants had good monomer loading, up to 4.72 monomer to surfactant by mass

The use of click-type reactions in the preparation of thermosets

Click chemistry has emerged as an effective polymerization method to obtain thermosets with enhanced properties for advanced applications. In this article, commonly used click reactions have been reviewed, highlighting their advantages in obtaining homogeneous polymer networks. The basic concepts necessary to understand network formation via click reactions, together with their main characteristics, are explained comprehensively. Some of the advanced applications of thermosets obtained by this methodology are also reviewed.Postprint (published version

Fabrication of POSS nano-composite membranes using plasma technology for solvent separation

This thesis developed an environmentally friendly plasma process to generate advanced separation membrane materials. The membranes of tunable properties exhibited high flux and found applications in solvent separation exhibiting promising performance for cost-effective dewatering of alcohol solutions

Self-Healing Polymer-based Nanocomposites using the Diels-Alder-reaction: Studies on the Influence of Composition on Self-Healing Properties

SiO2-nanoparticle-polymer–interfaces were tested according to their suitability as a DA - reversible crosslinking site. The role of the chemical composition of the polymer matrix was shown. Cuts of several millimeters could be healed within the siloxane-based nanocomposite, after reconnection of cut surfaces with the help of chloroform, by the DA reaction. The limit of interface-reactivity was investigated in a cofunctionalization study. Therefore, FexOy nanoparticles were functionalized with a monolayer DA-alkyl phosphonic acids. A drastic drop in conversion was recorded, when the attacking reagents were dodecyl derivatives of maleimide and furan instead of maleimide/methylfuran. This result indicates, that due to the sterical situation created by the attacking reagent on the surface only a minimal conversion with polymer chains is possible Therefore, diene and dienophile were distributed statistically within the matrix, instead of being located cumulative at the particle surface. Linear one-component polymers, consisting of diene, dienophile and one additional hydrogen bonding motive were synthesized using controlled radical polymerization techniques. Urea-group bearing spherosilicates were synthesized in high yields. By blending these both components, a hybrid material with double intrinsically reversible networks was received. The H bonds reconnect cut interfaces at 30°C, whereafter cuts in the mm-scale could be healed by the DA reaction

Preparation and characterization of mixed matrix membranes for gas separation and pervaporation

El objetivo principal de esta investigación fue desarrollar membranas de matriz mixta(MMMs) que pueda proveer un rendimiento superior que los polímeros puros para dos diferentes tipos de tecnologías de membranas (por ejemplo separación de gas y pervaporación). En la primera parte de esta tesis, el mejoramiento de la permeación de CO2 de un polímero commercial, como la polimida Matrimid®5218, fue abordada. En este punto, fue propuesta por primera vez la preparación de MMMs ternarias rellenando nanopartículas ZIF-8 (33.83 ± 6.2 nm) en la mezcla Matrimid®-PEG 200. Las MMMs fueron probadas a diferentes composiciones (50:50) y presiones de alimentación (de 2 a 8 bar). Las MMMs fueron también caracterizadas usando SEM, EDX, DSC, and TGA.Los resultados indicaron que la incorporación del 30 %p/p de nanopartículas condujo a incrementar la permeabilidad al CO2 en las MMM binarias (hasta 31.47 Barrer ) y ternarias (hasta 33.12 Barrer); destacando que la adición del PEG y el ZIF-8 mejoró la permeabilidad al CO2 (mas de tres veces) en comparación con las membranas Matrimid® puras (7.16 Barrer).El uso de esta poliimida comercial Matrimid®5218, como un polímero hidrofílico, ha sido también extendido a otra tecnología de membrane (por ejemplo la pervaporación).La potencialidad de esta polimida se relaciona con la separación de mezclas azeotrópicas orgánicas-orgánicas. En este punto, membranas de Matrimid®5218 fueron preparadas y probadas por primera vez en separación por pervaporación (PV) de la mezcla azeotrópica methanol (MeOH)- metil terc-butil éter (MTBE) (14.3 y 85.7%p/p,respectivamente). Los experimentos PV fueron llevados acabo a diferentes temperaturas(25-45ºC) y presiones de vacío (0.0538, 0.2400, 2.1000 mbar) en el permeado. Los resultados destacan que la temperatura (en el rango de 25-45 ºC) afectó principalmente la permeación del MeOH, produciendo un incremento en su flujo de permeado y el factor de separación también. Los mejores rendimientos de Matrimid® fueron a 45 ºC y 0.054 mbar, donde un flujo de permeado y un factor de separación de alrededor de 0.073 kg m-2 h-1 y 21.16, respectivamente, fueron alcanzados.En la última parte de esta tesis, el mejoramiento de otro polímero comercial, como elalcohol de polivinilo (PVA), fue propuesto para aplicaciones de PV. De este modo, unmaterial altamente hidrofílico, como el óxido de grafeno (GO), fue existosamentepreparado e incorporado en una matriz de PVA reticulado. Las MMM fueron probadaspara la deshidratación de etanol (10:90 %p/p agua-etanol) monitoreando su rendimientoen terminus de flujo total de permeado, flujo por componentes, así como su factor deseparación. El efecto del relleno fue analizado duplicando el contenido del GO (a 0.5,1.0, and 2.0 %p/p) en las MMMs. Además, las membranas fueron caracterizadas porFESEM, DSC, TGA, XRD, grado de hinchamiento, ángulo de contacto con agua, ypropiedades mecánicas. El mejor rendimiento de dichas MMMs (conteniendo 1 %p/p deGO) fue encontrado a 40 ºC, mostrando un factor de separación de 263 y un flujo depermeado de alrededor de 0.137 kg·m-2·h-1 (en el cual 0.133 kg·m-2·h-1 corresponde aagua). Este resultado representa una mejora del 75 % de la tasa de permeación originalde las membranas reticuladas de PVA pura.Finalmente, este trabajo reporta el mejoramiento de dos polímeros comerciales (talescomo poliimida Matrimid®5218 y alcohol de polivinilo). Es importante mencionar quetales polímeros fueron selecionados acorde a su consolidación en producción a grandeescala y su aplicación cercana a escala industrial. En general los capítulos tambiénabordan revisiones de literatura para seleccionar cada caso de estudio y así ser atendidosdurante esta investigación (por ejemplo separaciones CO2/CH4 y MeOH-MTBE, asícomo deshidratación de etanol). Además, esta tesis provee puntos relevantes enprocedimientos de preparación adecuados para obtener MMMs con buen rendimientThe main aim of this research work was to develop mixed matrix membranes (MMMs), which may provide superior performance compared to the base pristine polymers, for two different types of membrane-based technologies (e.g. gas separation and pervaporation). In the first part of the thesis, the enhancement of CO2 permeation of a commercial polymer, like Matrimid®5218 polyimide, was aimed. At this point, it is proposed, for the first time, the preparation of ternary MMMs based on the filling ZIF-8 nanoparticles (33.83 ± 6.2 nm) into Matrimid®-PEG 200 blend. The MMMs membranes were tested at fixed feed composition (50:50) and different feed pressures (from 2 to 8 bar). The MMMs were also characterized using SEM, EDX, DSC, and TGA. The results indicate that the incorporation of 30 wt.% of ZIF-8 nanoparticles leads to increase of CO2 permeability in binary (up to 31.47 Barrer) and ternary MMMs (up to 33.12 Barrer); pointing out that the addition of PEG and ZIF-8 enhanced the CO2 permeability (more than 3-folds) comparing to the neat Matrimid® membranes (7.16 Barrer). The use of this commercial Matrimid®5218 polyimide, as a hydrophilic polymer, has been also extended to other membrane technology (e.g. pervaporation). The potentiality of this polyimide deals with the separation of organic-organic azeotropic mixtures. Herein, Matrimid® membranes were prepared and tested, for the first time, in pervaporation (PV) separation of azeotropic methanol (MeOH)- methyl tert-butyl ether (MTBE) mixture (14.3 and 85.7%, respectively). The PV experiments were carried out at different feed temperatures (25-45ºC) and vacuum pressures (0.0538, 0.2400, 2.1000 mbar) at permeate side. The results pointed out that the feed temperature (in the range of 25-45 ºC) affected mainly the MeOH permeation producing an increasing on its partial permeate flux and separation factor as well. Importantly, the best performances of Matrimid® were found at 45 ºC and 0.054 mbar, where a permeate flux and a separation factor of about 0.073 kg m-2 h-1 and 21.16, respectively, were reached. In the last part of this thesis, the enhancement of another commercial polymer, like poly(vinyl alcohol) (PVA), was proposed for PV applications. In this way, a highly hydrophilic inorganic material, like graphene oxide (GO), was successfully prepared and incorporated into a cross-linked PVA matrix. The MMMs were tested for the dehydration of ethanol (10:90 wt. % water-ethanol), monitoring their performance in terms of total permeate flux, components fluxes, as well as their separation factor. The effect of filler was analyzed by doubling the GO content (at 0.5, 1.0, and 2.0 wt.%) in the MMMs. Furthermore, the membranes were characterized by FESEM, DSC, TGA, XRD, and measurements of degree of swelling, water contact angle, and mechanical properties. The best performance of such MMMs (containing 1 wt.% of GO) was found at 40 ºC, displaying a separation factor of 263 and a permeate flux of about 0.137 kg·m-2·h-1 (in which 0.133 kg·m-2·h-1 corresponds to water). This result represents a 75 % enhancement of the original permeation rate of pristine cross-linked PVA membranes. Finally, this work reports the enhancement of two commercial polymers (such as Matrimid®5218 polyimide and poly(vinyl alcohol) (PVA)). It is important to mention that such polymers were chosen according to their consolidation in large-scale production and their near application at industrial scale. In general, the chapters also address the literature reviews to select each case of study, and thus to be attended during this research (e.g. CO2/CH4 and MeOH-MTBE separations as well as ethanol dehydration). Moreover, this thesis provides relevant insights into the suitable preparation procedures to reach high performing MMMs<br /

Politiouretanos termoestables vitriméricos con propiedades mejoradas de reciclabilidad

En aquesta tesi s'ha avançat en l'estudi de xarxes termoestables de politiouretan (PTU) reciclables, gràcies al bescanvi dinàmic entre grups tiouretà. Els materials s'han preparat per reacció entre tiols i isocianats polifuncionals, tant en condicions àcides com bàsiques. A més, s'han estudiat les aplicacions d'aquests materials com a materials reciclables, autoreparables i com a matrius de materials compostos. Buscant una major sostenibilitat, s'ha estudiat l'activitat catalítica d'alternatives als compostos d'estany (IV), els més utilitzats a escala industrial. També s'han preparat tiols a partir de derivats de la biomassa, i s'ha estudiat el seu paper com substitut de tiols derivats de combustibles fòssils.En esta tesis se ha avanzado en el estudio de redes termoestables de politiouretano (PTU) reciclables, debido al intercambio dinámico entre grupos tiouretano. Los materiales se han preparado por reacción entre tioles e isocianatos polifuncionales, tanto en condiciones ácidas como básicas. Además, se han estudiado las aplicaciones de estos materiales como materiales reciclables y autorreparables, y como matrices de composites. En búsqueda de una mayor sostenibilidad, se ha estudiado la actividad catalítica de alternativas a los compuestos de estaño (IV), los más empleados a nivel industrial. También se han preparado tioles a partir de derivados de la biomasa, y se ha estudiado su papel como sustituto de tioles derivados de combustibles fósiles.In this thesis, progress has been made in the study of recyclable polythiourethane (PTU) thermosetting networks, due to the dynamic exchange between thiourethane groups. The materials have been prepared by reaction between polyfunctional thiols and isocyanates, both under acidic and basic conditions. In addition, the applications of these materials as recyclable and self-healing materials and as matrix composite have been studied. In search of a greater sustainability, the catalytic activity of alternatives to tin (IV) compounds, the most widely used at an industrial level, has been studied. Different thiols have also been prepared from biomass derivatives, and their role as a substitute for thiols derived from fossil fuels has been studied