Fluorinated lactide-based copolymers

Disclosed is a process for producing lactide-based copolymers and the copolymers produced by this process. Disclosed copolymers are formed in one embodiment through the copolymerization of a lactide monomer with a fluorinated diol, for example a perfluorinated polyether monomer, oligomer or copolymer. The disclosed materials may display improved mechanical characteristics, hydrolytic characteristics, and thermal characteristics as compared to previously known lactide-based materials

Transferring a molecular foundation model for polymer property predictions

Transformer-based large language models have remarkable potential to accelerate design optimization for applications such as drug development and materials discovery. Self-supervised pretraining of transformer models requires large-scale datasets, which are often sparsely populated in topical areas such as polymer science. State-of-the-art approaches for polymers conduct data augmentation to generate additional samples but unavoidably incurs extra computational costs. In contrast, large-scale open-source datasets are available for small molecules and provide a potential solution to data scarcity through transfer learning. In this work, we show that using transformers pretrained on small molecules and fine-tuned on polymer properties achieve comparable accuracy to those trained on augmented polymer datasets for a series of benchmark prediction tasks

Synergistic actions of melatonin in combination with anti-parkinsonian drugs in experimental model of Parkinson’s disease

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by progressive degeneration and loss of nigrostriatal dopaminergic neurons in the midbrain, A9 substantia nigra neurons leading to severe striatal dopamine (DA) depletion resulting in tremor, rigidity and hypokinesia (Carlsson, 2002). PD is named after James Parkinson who first described the disease as “Shaking Palsy” (Paralysis Agitans) in his classic monograph “An essay on the Shaking Palsy” (Parkinson, 1817). This debilitating disorder has no cure existing, and recent epidemiological studies suggest an increasing trend in its incidents; predicting an alarming 2-fold increase in affected population by 2030 in several countries (Dorsey et al., 2007). Currently used drugs for PD provides symptomatic relief, and are based on increasing the striatal levels of DA, or controlling the DA transmission. However, these drugs are generally short acting, and with time develop serious side effects. There are cases when the drugs need to be discontinued due to exacerbation of DA-mediated effects. At this juncture, there is a great need of alternative therapies, or designs that would effectively reduce the dose of drugs that causes ‘on-off’ effects, dyskinesias, other undesirable motor effects, non-motor complications, and slower the progression of the disease. One of such effective therapy is using a peripheral aromatic amino acid decarboxylase inhibitor, carbidopa along with L-3,4-dihydroxyphenylalanine (L-DOPA). The present study mainly addressed such alternative approaches so as to find better therapeutic agents that may synergize with the existing PD drugs

Mechanical, thermal, morphological, and rheological characteristics of high performance 3D-printing lignin-based composites for additive manufacturing applications

The article presents different mechanical, thermal and rheological data corresponding to the morphological formation within various renewable lignin-based composites containing acrylonitrile butadiene styrene (ABS), acrylonitrile butadiene rubber (NBR41, 41 mol% nitrile content), and carbon fibers (CFs). The data of 3D-printing properties and morphology of 3D-printed layers of selected lignin-based composites are revealed. This data is related to our recent research article entitled “A general method to improve 3D-printability and inter-layer adhesion in lignin-based composites” (Nguyen et al., 2018 [1])

Data of thermally active lignin-linkages and shape memory of lignin-rubber composites

This data article presents the utilization of thermally dynamic covalent bonds of lignin linkages such as β–O–4′, Cα–O of β–5′ phenylcoumaran, and β–β resinol to modify the thermomechanical properties of high loading lignin-nitrile rubber composites. These thermally active lignin linkages can be triggered at 180 °C to generate free-radicals for crosslinking reactions. The evolution of crosslinking density was measured in-situ using dynamic mechanical analysis and rheological characterization. The shape programmability and shape recovery of these composites were determined by both ex-situ and in-situ methods. The thermally modified composites exhibited excellent shape memory properties. The data in this article are related to our recent research article entitled “Responsive lignin for shape memory applications” (Nguyen et al., 2018)

Roll-to-Roll Processing of Silicon Carbide Nanoparticle-Deposited Carbon Fiber for Multifunctional Composites

This work provides a proof of principle that a high volume, continuous throughput fiber coating process can be used to integrate semiconducting nanoparticles on carbon fiber surfaces to create multifunctional composites. By embedding silicon carbide nanoparticles in the fiber sizing, subsequent composite fabrication methods are used to create unidirectional fiber-reinforced composites with enhanced structural health monitoring (SHM) sensitivity and increased interlaminar strength. Additional investigations into the mechanical damping behavior of these functional composites reveal a significantly increased loss factor at the glass-transition temperature ranging from a 65 to 257% increase. Composites with both increased interlaminar strength and SHM sensitivity are produced from a variety of epoxy and silicon carbide nanoparticle concentrations. Overall, the best performing composite in terms of combined performance shows an increase of 47.5% in SHM sensitivity and 7.7% increase in interlaminar strength. This work demonstrates successful and efficient integration of nanoparticle synthesis into large-scale, structural applications

Recycling Waste Polyester via Modification with a Renewable Fatty Acid for Enhanced Processability

Polyethylene terephthalate (PET) waste often contains a large amount of thermally unstable contaminants and additives that negatively impacts processing. A reduced processing temperature is desired. In this work, we report using a renewably sourced tall oil fatty acid (TOFA) as a modifier for recycled PET. To that end, PET was compounded with TOFA at different concentrations and extruded at 240 °C. Phase transition behaviors characterized by thermal and dynamic mechanical analyses exhibit shifts in the melting and recrystallization temperatures of PET to lower temperatures and depression of glass transition temperature from 91 to 65 °C. Addition of TOFA also creates crystal-phase imperfection that slows recrystallization, an important processing parameter. Changes in the morphology of plasticized PET reduces and stabilizes the melt viscosity at 240 and 250 °C. Melt-spun, undrawn continuous filaments of diameter 36–46 μm made from these low-melting PET exhibit 29–38 MPa tensile strength, 2.7–2.8 GPa tensile modulus, and 20–36% elongation. These results suggest a potential path for reusing waste PET as high-performance polymeric fibers

CRADA Final Report: Materials Development For Pulp and Paper Mills, Task 9 Proof of Commercial Concept: Commodity Carbon Fibers From Weyerhaeuser Lignin Based Fibers

Tasks were assigned to Oak Ridge National Laboratory (ORNL) researchers for the development of lignin-based carbon fiber from a specific precursor that was produced by the Participant (Weyerhaeuser Corporation). These tasks included characterization of precursor polymers and fibers; and the development of conversion parameters for the fibers. ORNL researchers provided recommendations for in-house characterization of the precursor at the participant's laboratory. During the early stage of the precursor fiber production trials of various spools of fibers with varied compositions were produced. Some of those samples were sent to ORNL (by the Participant) for the development of conversion protocol. The trial tow samples were oxidized at ORNL's precursor evaluation system (PES), a bench-scale facility consisting of an oven, filament winder, tension controller, and a let off creel. The PES is a modular tool useful for the development of precursor conversion protocol. It can handle a single filament to a large single tow (50k filaments). It can also offer precise tensioning for few-filament tows. In the PES, after oxidation, fibers are typically carbonized first at low temperature, {le} 600 C, and subsequently at a higher temperature, {le} 1200 C with controlled residence time. ORNL has recently installed a new carbonization furnace with 1700 C limit and a furnace with 2500 C capacity is under installation. A protocol for the oxidation and carbonization of the trial precursor fibers was developed. Oxidized fiber with a density of 1.46 g/cc (oxidation time: 90 min) shows qualitative flame retardancy via simple flame test (fibers do not catch fire or shrink when exposed to flame). Oxidized and carbonized filaments of the Weyerhaeuser precursor fibers show moderate mechanical properties and 47-51 % carbon yield (based on oxidized fiber mass) after carbonization between 1000-1400 C. The properties of fibers from nonoptimized composition and processing parameters indicate the potential of low-cost, low-end carbon fibers based on renewable resource materials. Further work is necessary to produce high quality precursor and the corresponding carbonized filaments of superior properties