Chemical Structure Drives Memory Effects in the Crystallization of Homopolymers

Unformatted post-print version of the accepted articleAlthough the study of melt memory has attracted much interest, the effect of polymer chemical structure on its origin has not been fully elucidated. In this work, we study melt memory effects by Differential Scanning Calorimetry employing a self-nucleation protocol. We use homologous series of homopolymers containing different polar groups and different number of methylene groups in their repeating units: polycarbonate, polyesters, polyethers and polyamides. We show that melt memory in homopolymers is generally controlled by the strength of the intermolecular interactions. The incorporation of methylene groups reduces melt memory effects by decreasing the strength of segmental chain interactions, which is reflected by the decrease in dipolar moments and solubility parameters. This work presents for the first time a unified view of the melt memory effects in different homopolymers.We acknowledge funding from MINECO MAT2017-83014-C2-1-P project, and from the Basque Government through grant IT1309-19. L. S acknowledges FPU predoctoral grant and the postdoctoral grant from Basque Governnment. We would also like to thank the financial support provided by the BIODEST project; this project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 778092

Poli(butilen adipato-ko-tereftalato)/Fenoxi sistemaren nahaskortasuna eta hesi-propietateen aldaketa

Biodegradable and compostable Poly(butylene adipate-co-terephthalate) (PBAT) copolymer has been stud ied. lt has good mechanical properties, but in order to be used in industrial appl ications its barrier properties must be improved significant ly.For this purpose it has been mixed with phenoxy resin. Miscibility is established through determ ination of the glass transition temperature. The relationship between the T~ and composition has been stud ied using different models, since th is re lat ionship reflects the strength of the interactions. Water vapou r and oxygen permeability ha ve been measured to determine transpon properties. The results indicare that the PBAT/Ph system is miscib le o ver the en tire composition range. The analysis of the transport properties results shows that the addition of phenoxy causes a sharp decrease in water vapour and oxygen permeability, wh ich is beneficia! for industrial applications .; Biodegradagarria eta konpostagarria den kopol imero bat aztertu da, poli( butilen adipato-ko-tereftalatoa) (PBAT) hain zuzen ere. Propietate mekaniko egokiak dituen arren , aplikazio industrialetan erabilgarria izan dad in bere hesi-propietateak nabarmen hobetu behar dira. Helburu hori lortu nahian, fenoxi erretxinarekin (Ph) nahastu da . Sistemaren nahaskortasuna karakterizatu da beira-trantsizioaren tenperatura zehaztuz . T~-ak konpos izioaren arabera jasaten duen aldaketa azaltzeko badaude hainbat eredu teoriko , nahastea osatzen duten bi osagaien arteko elkarrekintzen isla direnak.Ondoren, ur-lurrunarekiko eta oxigenoarekiko iragazkortasuna neurtu da sistemaren hesi-propietateak zehazteko. Lorturiko emaitzek aditzera eman dutenez PBAT/ Ph sistema nahaskorra da azterturiko konposizio guztietan. Hesi-propietateen emaitzak aztertuz. ikusi da fenoxiaren gehikuntzak ur-lurrunarekiko zein oxigenoarekiko iragazkortasunaren jaitsiera esangurats ua dakarrela; ahalmen hori baliagarria izan daiteke material hau industrian erabiltzeko unean

Lactide-Valerolactone Copolymers for Packaging Applications

Lactide-valerolactone copolymers have potential application in the packaging sector. Different copolymers were synthesized, and the kinetics of the copolymerization reactions and the microstructure of the copolymers were analysed. Lactide showed higher reactivity than valerolactone which leads to composition drift through the reaction. Thermal, mechanical and barrier properties of the selected copolymers were studied. Overall, the incorporation of valerolactone results in copolymers with higher ductility than poly(lactide) with intermediate water and oxygen permeability which makes these materials appropriate candidates for use in the packaging sector.The financial support from the Basque Government (GC IT-1313-19, PPGA 19/18 and GIU 19/077) and the Spanish Ministry of Innovation and Competitiveness MINECO (PID2019-106236GB-I00) is acknowledged. A. Sangroniz thanks the Basque Government for the PhD grant. L. Sangroniz thanks the Basque Government for the postdoctoral fellowship (POSDOC). S. Hamzehlou acknowledges the University of the Basque Country (UPV/EHU) for the “Contratación para la especialización de personal investigador doctor” postdoctoral grant. The authors thank the technical and human support provided by Sofia Guezala (NMR SGIker) and European Funding (ERDF and ESF)

Polilaktida plastifikatua elikagaien ontziratzerako: plastifikatzailearen pisu molekularraren eragina bolumen aske eta hesi-ezaugarrietan

Nowadays the main strategy to solve the problem of plastic waste is to use biodegradable polymers. Among them, polylactide has attracted a great attention. However in order to be suitable for packaging applications its ductility must be improved. With this aim, polylactide has been blended with polyethylene glycol (PEG). More exactly, three different polyethylene glycols have been used and the effect of the molecular weight on the physical properties has been analysed. The addition of the plasticizer reduces the glass transition temperature, especially the polyethylene glycol with the highest molecular weight, and the crystallinity level is increased. The changes in the free volume fraction are small but with high plasticizer content the free volume fraction increases considerably. Regarding the barrier character, the oxygen permeability is reduced or maintained, whereas carbon dioxide and water permeability increase with the addition of the plasticizer. It is worthy to note that among the blends containing different plasticizers, the system containing the plasticizer with the lowest molecular weight shows the highest permeability values. In the case of systems containing PEG 1500 and PEG 4600 the changes are subtle and apart from the molecular weight, other factors such as the glass transition temperature, the degree of crystallinity and the free volume influence the transport properties.; Gaur egun plastikoen hondakinek sorrarazten duten arazoari aurre egiteko aukera bat polimero biodegradagarriak erabiltzea da. Horien artean polilaktidak interes handia piztu du, baina elikagaien ontziratzean erabilgarria izan dadin bere deformakortasuna hobetu behar da. Helburu horrekin lan honetan polilaktidari polietilenglikol (PEG) plastifikatzailea gehitu zaio. Zehazki pisu molekular desberdina daukaten hiru polietilenglikol erabili dira, eta pisu molekularrak propietate fisikoetan daukan eragina aztertu da. Plastifikatzailea gehitutakoan beira-trantsizio tenperatura jaitsi egiten da, bereziki pisu molekular altuena duen polietilenglikola gehitutakoan, eta kristalinitate-maila handiagoa egiten da. Bolumen askean aldaketak txikiak badira ere, plastifikatzaile kantitatea handitu ahala, bolumen askea nabarmen handiagoa egiten da. Hesi ezaugarriei dagokienez, oxigenoaren kasuan iragazkortasuna murriztu edo bere horretan mantentzen da; karbono dioxidoaren eta uraren kasuan, ordea, iragazkortasuna handitu egiten da plastifikatzaile kantitatearekin batera. Aipatzekoa da plastifikatzaile nahaste desberdinen artean pisu molekular baxueneko plastifikatzailea duen sistemak azaltzen dituela iragazkortasun balio altuenak. PEG 1500 eta PEG 4600 sistemen kasuan aldaketak ez dira hain nabariak, eta, pisu molekularraz gainera, beste faktore batzuek, hala nola beira-trantsizio tenperaturak, kristalinitate-mailak eta bolumen askeak, ere eragina daukate

Poly(hydroxy acids) derived from the self-condensation of hydroxy acids: from polymerization to end-of-life options

[EN] Poly(hydroxy acids) have been gaining increasing attention in the search for novel sustainable materials to replace petrochemical polymers in packaging applications. Poly(hydroxy acids) are polyesters that are obtained using hydroxy acids as the starting materials, which are derived from renewable resources and biowaste. These biopolymers have attracted a lot of attention since some of them will be in the near future competitive in price to polyolefins, show excellent mechanical and barrier properties, and can be potentially recycled by physical and chemical routes. Most of the current poly(hydroxy acids) are mainly prepared by ring-opening polymerization (ROP) of cyclic monomers derived from hydroxy acids. However, their direct polymerization has received much less attention, while one of the advantages of hydroxy acids resides in the presence of an electrophile and a nucleophile in a single molecule that makes them ideal A-B type monomers for self-condensation. This review focuses on the preparation of poly(hydroxy acids) by the self-condensation polymerization of hydroxy acids. Moreover, their end-of-life options are also evaluated considering not only their biodegradability but also their potential to be chemically recycledThe authors thank the European Commission (EC) for financial support through the project SUSPOL-EJDH2020-ITN-2014-642671 and the Spanish Ministry of Science and Innovation (MICI) through the projects RTI2018-097249-B-C21, MAT2017-83373-R, and MAT-2016-78527-P. S. Torres-Giner also acknowledges MICI for his Juan de la Cierva-Incorporacion contract (IJCI-2016-29675) and the financial support received during his stay at the Institute for Polymer Materials (POLYMAT)Gabirondo, E.; Sangroniz, A.; Etxeberria, A.; Torres-Giner, S.; Sardon, H. (2020). Poly(hydroxy acids) derived from the self-condensation of hydroxy acids: from polymerization to end-of-life options. Polymer Chemistry. 11(30):4861-4874. https://doi.org/10.1039/D0PY00088DS48614874113

Lactide-Valerolactone Copolymers for Packaging Applications

Lactide-valerolactone copolymers have potential application in the packaging sector. Different copolymers were synthesized, and the kinetics of the copolymerization reactions and the microstructure of the copolymers were analysed. Lactide showed higher reactivity than valerolactone which leads to composition drift through the reaction. Thermal, mechanical and barrier properties of the selected copolymers were studied. Overall, the incorporation of valerolactone results in copolymers with higher ductility than poly(lactide) with intermediate water and oxygen permeability which makes these materials appropriate candidates for use in the packaging sector

Ontziratzerako material polimeriko jasangarrien garapena: polimero biodegradagarriak eta kimikoki birziklagarriak.

593 p.The main aim of this thesis has been the development of sustainable polymeric materials withpotential applications in food packaging and the study of the relationship between differentparameters and the transport properties. For that purpose, different systems have been analysed: a)polymer blends based on a biodegradable polymer with improved barrier properties whilemaintaining an adequate hydrolytic degradation. b) Nanocomposites that show improved barrierproperties. c) Transport properties of organic solvents on biodegradable polymers. d) Synthesis offully chemically recyclable copolymers that present outstanding barrier and mechanical propertiesthat are similar to commercial poly(ethylene terephthalate) and poly(ethylene) and better thanbiodegradable poly(lactide) and poly(hydroxybutyrate) ones.Polyma

Ontziratzerako material polimeriko jasangarrien garapena: polimero biodegradagarriak eta kimikoki birziklagarriak.

593 p.The main aim of this thesis has been the development of sustainable polymeric materials withpotential applications in food packaging and the study of the relationship between differentparameters and the transport properties. For that purpose, different systems have been analysed: a)polymer blends based on a biodegradable polymer with improved barrier properties whilemaintaining an adequate hydrolytic degradation. b) Nanocomposites that show improved barrierproperties. c) Transport properties of organic solvents on biodegradable polymers. d) Synthesis offully chemically recyclable copolymers that present outstanding barrier and mechanical propertiesthat are similar to commercial poly(ethylene terephthalate) and poly(ethylene) and better thanbiodegradable poly(lactide) and poly(hydroxybutyrate) ones.Polyma

Metal-free initiators pave the way for chemically recyclable polymers with industrially relevant properties

To solve the environmental disaster that is generated by legacy plastics accumulation, researchers are looking to design plastics with enhanced end-of-life options, but many circular plastics do not meet industrial requirements. Here, we highlight a metal-free approach to produce chemically recyclable poly(1,3-dioxolane) with ultra-high molecular weight and comparable properties to one of the most produced plastics, polyethylene