Polylactide- block-poly(γ-methyl-ε-caprolactone)- block-polylactide (LML) is a sustainable thermoplastic elastomer (TPE) candidate that exhibits competitive mechanical properties as compared to traditional styrenic TPEs. The relatively low glass transition temperature of the polylactide endblocks, however, results in stress relaxation and low levels of elastic recovery. We report the synthesis and characterization of poly(γ-methyl-ε-caprolactone) (PMCL) and LML end-functionalized with ureidopyrimidinone (UPy) hydrogen-bonding moieties to improve the elastic performance of these polymers. Although UPy-functionalized PMCL shows dynamical mechanical behavior that is distinct from the unfunctionalized homopolymer, it does not exhibit elastomeric behavior at room temperature. The addition of UPy endgroups to LML increases the ultimate tensile strength, elongation at break, and tensile toughness compared to unfunctionalized LML. Stress relaxation studies at a fixed strain show reduced levels of stress relaxation in LML with UPy endgroups. The stress relaxation was further reduced by including semicrystalline poly(( S, S)-lactide) as endblocks with UPy endgroups.
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http://dx.doi.org/10.1021/acs.biomac.9b00411 | DOI Listing |
ACS Phys Chem Au
January 2025
Department of Chemistry, McGill University, Montréal, Québec H3A 0B8, Canada.
Amorphous solids form an enormous and underutilized class of materials. In order to drive the discovery of new useful amorphous materials further we need to achieve a closer convergence between computational and experimental methods. In this review, we highlight some of the important gaps between computational simulations and experiments, discuss popular state-of-the-art computational techniques such as the Activation Relaxation Technique (ARTn) and Reverse Monte Carlo (RMC), and introduce more recent advances: machine learning interatomic potentials (MLIPs) and generative machine learning for simulations of amorphous matter (e.
View Article and Find Full Text PDFNutrients
January 2025
Department of Exercise and Nutrition Sciences, Milken Institute School of Public Health, The George Washington University, Washington, DC 20052, USA.
The undergraduate college years are a critical transition period for young adults in establishing life-long health behaviors. : Within the FRESH Study, we aimed to understand the relationship between perceived physical health, perceived mental health, and specific health metrics (e.g.
View Article and Find Full Text PDFNutrients
January 2025
Department of Obstetrics and Gynaecology, Semmelweis University, Üllői Street 78/a, 1082 Budapest, Hungary.
Background/objectives: Both hyperandrogenism (HA) and vitamin D deficiency (VDD) can separately lead to impaired vascular reactivity and ovulatory dysfunction in fertile females. The aim was to examine the early interactions of these states in a rat model of PCOS.
Methods: Four-week-old adolescent female rats were divided into four groups: vitamin D (VD)-supplemented ( = 12); VD-supplemented and testosterone-treated ( = 12); VDD- ( = 11) and VDD-and-testosterone-treated ( = 11).
Pharmaceuticals (Basel)
January 2025
Department of Translational Research and New Surgical and Medical Technologies in Medicine and Surgery, University of Pisa, 56126 Pisa, Italy.
Psychedelics, historically celebrated for their cultural and spiritual significance, have emerged as potential breakthrough therapeutic agents due to their profound effects on consciousness, emotional processing, mood, and neural plasticity. This review explores the mechanisms underlying psychedelics' effects, focusing on their ability to modulate brain connectivity and neural circuit activity, including the default mode network (DMN), cortico-striatal thalamo-cortical (CSTC) loops, and the relaxed beliefs under psychedelics (REBUS) model. Advanced neuroimaging techniques reveal psychedelics' capacity to enhance functional connectivity between sensory cerebral areas while reducing the connections between associative brain areas, decreasing the rigidity and rendering the brain more plastic and susceptible to external changings, offering insights into their therapeutic outcome.
View Article and Find Full Text PDFLife (Basel)
December 2024
Workgroup for Science Management, Semmelweis University Doctoral College, 1085 Budapest, Hungary.
According to World Health Organization (WHO) data, 16% of people are affected by infertility across the globe. One underlying factor is the age-related decline of ovarian reserve (DOR), which can lead to a higher chance of infertility and has no widely accepted treatment currently. Specific supplements and moderate exercise have been shown to improve fertility; however, there is no consensus to date on the type of exercise providing the best results.
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