Design Of Polymeric Materials Research Articles

Nonlinear Impact Force Reduction of Layered Polymers with the Damage-Trap Interface

In this paper, a damage-trap material interface design of polymeric materials was proposed. Towards that, baseline and layered Polymethyl methacrylate (PMMA) and Polycarbonate specimens were fabricated with a Loctite 5083 adhesive layer between the interfaces. Out-of-plane impact experiments were conducted and found that the maximum impact force was reduced in layered polymers with so-called “damage-trap material interfaces”. At the impact energy of 20 J, the maximum impact force of the layered PMMA specimens with the 5083 adhesive was reduced by 60% compared to the identical specimens without any adhesive bonding. For the layered Polycarbonate specimens with the 5083 adhesive bonding, the maximum impact force was reduced by 20% and energy absorption was increased by 130%. Simplified contact mechanics analysis showed that the low Young’s modulus of the 5083 adhesive layers was a key parameter in reducing impact force and damage. Therefore, a simple and effective way to design layered materials with improved impact resistance was proposed.

SYNTHESIS OF A NOVEL SILICONE- AND TRIAZINE-BASED COPOLYMER WITH FURFURYL SIDE GROUPS

S-triazine derivatives are known to have great potential in diversifying the structural design of polymer materials due to the stepwise reaction of cyanuric chloride, particularly in optoelectronic applications. In addition, the hydrogen bonds formed by the triazine ring are known to play an important role in molecular arrangement, providing triazine-based polymer materials with excellent mechanical properties. In the present work, a triazine-furan precursor will be combined with polydimethylsiloxane (PDMS) and polyoxypropylenediamine to create a novel polymer that bears furfuryl side groups. This polymer has great potential to be used for self-healing applications due to the reversibility of triazine π-π stacking and hydrogen bonding as well as the ability of the furfuryl group to form dynamic covalent bonds. Thin-layer chromatography (TLC) and gel permeation chromatography (GPC) was used to investigate the reaction conditions (GPC). The research of this reaction revealed that the best conditions for the synthesis of this copolymer were at a temperature of 110 oC for 24 hours and determined an average molecular weight (Mn) of around 19800 (g/mol). Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) are used to determine the structure of the synthesized compounds. Besides that, from the 1H-NMR spectrum NMR was found that feeding molar of 21.32/1/19.50 for TF, PDMS, and Jeffamine, respectively.

When Polymer Chains Are Highly Aligned: A Perspective on Extensional Rheology

We provide a Perspective on recent findings in extensional rheology for polymer melts and solutions with different macromolecular architectures. For linear polymer systems, we focus on the argument of flow-induced friction reduction and provide our comments from an experimental point of view. For branched polymers, we provide our understanding on how to control extensional viscosity for polymers with different zero-shear-rate viscosity based on recent experimental results of star and comb polymer melts. For ring polymers, we summarize the recent progress in extensional rheology and provide our view on what would be interesting for further investigation. On the basis of the above results and discussions, we show that extensional rheology is complicated for even very simple molecular architectures. More data from both experiments and simulations are important for improvement of a fundamental understanding and development of theories, which is essential for molecular design of polymer materials.

Multiscale Constitutive Modeling of the Mechanical Properties of Polypropylene Fibers from Molecular Simulation Data

We present a multiscale approach to create a constitutive model that predicts the mechanical properties of polypropylene fibers based on chemical and physical characteristics. The development of this method relies on validation with experimental stress–strain curves from nine different isotactic polypropylene (iPP) fibers with their varying molecular weight characteristics, Hermans orientation factors, and crystallinity. Complementary molecular models were built by using molecular dynamics (MD) simulations with united atom models. Tensile deformation simulations adapting a quasi-static procedure resulted in stress–strain curves that aligned well with the experimentally measured ones. A neural network model was trained on the MD simulation data to create correlations that predict parameters for a chosen constitutive model that describes the mechanical properties of the polypropylene fibers. This computational approach is amenable to be applied to polymer fiber systems and aims to aid in the design of polymeric materials to achieve targeted mechanical properties.

Functional Materials and Devices for XR (VR/AR/MR) Applications

Functional Materials and Devices for XR (VR/AR/MR) Applications

Deep Learning of Binary Solution Phase Behavior of Polystyrene.

Predicting binary solution phase behavior of polymers has remained a challenge since the early theory of Flory-Huggins, hindering the processing, synthesis, and design of polymeric materials. Herein, we take a complementary data-driven approach by building a machine learning framework to make fast and accurate predictions of polymer solution cloud point temperatures. Using polystyrene, both upper and lower critical solution temperatures are predicted within experimental uncertainty (1-2 °C) with a deep neural network, Gaussian process regression (GPR) model, and a combination of polymer, solvent, and state features. The GPR model also enables intelligent exploration of solution phase space, where as little as 25 cloud points are required to make predictions within 2 °C for polystyrene of arbitrary molecular weight in cyclohexane. This study demonstrates the effectiveness of machine learning for the prediction of liquid-liquid equilibrium of polymer solutions and establishes a framework to incorporate other polymers and complex macromolecular architectures.

Tuning the permeability of regular polymeric networks by the cross-link ratio.

The amount of cross-linking in the design of polymer materials is a key parameter for the modification of numerous physical properties, importantly, the permeability to molecular solutes. We consider networks with a diamond-like architecture and different cross-link ratios, concurring with a wide range of the polymer volume fraction. We particularly focus on the effect and the competition of two independent component-specific solute-polymer interactions, i.e., we distinguish between chain-monomers and cross-linkers, which individually act on the solutes and are altered to cover attractive and repulsive regimes. For this purpose, we employ coarse-grained, Langevin computer simulations to study how the cross-link ratio of polymer networks controls the solute partitioning, diffusion, and permeability. We observe different qualitative behaviors as a function of the cross-link ratio and interaction strengths. The permeability can be tuned ranging over two orders of magnitude relative to the reference bulk permeability. Finally, we provide scaling theories for the partitioning and diffusion that explicitly account for the component-specific interactions as well as the cross-link ratio and the polymer volume fraction. These are in overall good agreement with the simulation results and grant insight into the underlying physics, rationalizing how the cross-link ratio can be exploited to tune the solute permeability of polymeric networks.

High-performance laminate material based on polyurethane and epoxide reinforced by silica particles from rice husk used for intelligent pedestrian crossings

Intelligent pedestrian crossings were made with the aim to increase pedestrian safety at poorly lit locations. New technologies include the design of polymer materials that have high performance by optimizing properties such as compression, tensile and impact strengths, wear resistance, hardness and transparency. The desired properties are set up to face the demands of a heavy daily traffic load and enable the functionality. Laminate material consists of the epoxy composite reinforced with silica (SiO2) derived from rice husk waste and a protective thermoplastic polyurethane layer. The top layer of the laminate material is a transparent thermoplastic polyurethane (TPU) serving as a protective layer with high wear resistance and good adhesion with epoxy composite. Silica obtained from rice husk waste was used in reinforcing of the epoxide in order to improve the mechanical properties, diffuse the light, improve the adhesion with TPU and decrease the production costs. Micro-Vickers hardness of the epoxy composite was increased by 70% with the addition of 15 wt% of SiO2. Impact energy of the epoxy composite with 15 wt% of SiO2 was increased by 272.9% after adding the TPU layer. Compressive strength of the epoxy resin is improved by 16.2% by reinforcement with 15 wt% of SiO2, while the laminate composite material showed 207% higher compressive strength than the commonly used asphalt pavement. Moreover, the addition of 15 wt% of SiO2 improved the adhesion between epoxy composite and TPU layer (11.2%). Thus, obtained laminated material made of the epoxy composite with 15 wt% of SiO2 (obtained from rice husk waste) and TPU598 showed mechanical properties and LED light transmission/diffusion appropriate for application in the intelligent pedestrian crossings.

Design of polymeric materials: Experiences and prescriptions

AbstractAs process engineering has matured, research interest has shifted towards polymer product quality. In the past 20 years or so, the shift has progressed even further, as interest in polymer product quality has morphed into polymer product design. Product design is intended to be a targeted pursuit of optimal conditions that will yield polymers with desirable properties for a specific application. This can be achieved by following a systematic design framework that employs sequential, iterative steps informed by prior knowledge and experience. This overview provides some background information regarding the need for design (including some examples from previous experience), especially in terms of structure‐property relationships. When links between kinetics (synthesis conditions), polymer structure, and application properties are well‐understood, it becomes possible to essentially reverse‐engineer the polymeric material; the researcher can start with known application requirements and synthesize polymers with tailor‐made properties using an optimized recipe (according to the polymerization kinetics). A suggested design approach is presented herein, followed by the application of the design approach to two large case studies. The number of applications for polymeric materials is essentially limitless; the current work provides typical examples of a systematic polymeric material design framework (and related case studies).

Macromolecular Engineering by Applying Concurrent Reactions with ATRP.

Modern polymeric material design often involves precise tailoring of molecular/supramolecular structures which is also called macromolecular engineering. The available tools for molecular structure tailoring are controlled/living polymerization methods, click chemistry, supramolecular polymerization, self-assembly, among others. When polymeric materials with complex molecular architectures are targeted, it usually takes several steps of reactions to obtain the aimed product. Concurrent polymerization methods, i.e., two or more reaction mechanisms, steps, or procedures take place simultaneously instead of sequentially, can significantly reduce the complexity of the reaction procedure or provide special molecular architectures that would be otherwise very difficult to synthesize. Atom transfer radical polymerization, ATRP, has been widely applied in concurrent polymerization reactions and resulted in improved efficiency in macromolecular engineering. This perspective summarizes reported studies employing concurrent polymerization methods with ATRP as one of the reaction components and highlights future research directions in this area.

Environment-dependent single-chain mechanics of synthetic polymers and biomacromolecules by atomic force microscopy-based single-molecule force spectroscopy and the implications for advanced polymer materials.

"The Tao begets the One. One begets all things of the world." This quote from Tao Te Ching is still inspiring for scientists in chemistry and materials science: The "One" can refer to a single molecule. A macroscopic material is composed of numerous molecules. Although the relationship between the properties of the single molecule and macroscopic material is not well understood yet, it is expected that a deeper understanding of the single-chain mechanics of macromolecules will certainly facilitate the development of materials science. Atomic force microscopy-based single-molecule force spectroscopy (AFM-SMFS) has been exploited extensively as a powerful tool to study the single-chain behaviors of macromolecules. In this review, we summarize the recent advances in the emerging field of environment-dependent single-chain mechanics of synthetic polymers and biomacromolecules by means of AFM-SMFS. First, the single-chain inherent elasticities of several typical linear macromolecules are introduced, which are also confirmed by one of three polymer models with theoretical elasticities of the corresponding macromolecules obtained from quantum mechanical (QM) calculations. Then, the effects of the external environments on the single-chain mechanics of synthetic polymers and biomacromolecules are reviewed. Finally, the impacts of single-chain mechanics of macromolecules on the development of polymer science especially polymer materials are illustrated.

Rational molecular design of polymeric materials toward efficient triboelectric energy harvesting

In the periodic table, halogenic elements have a larger electron affinity (EA = −270~−349 kJ/mol) than any other group, allowing them to accommodate extra electrons for triboelectric energy harvesting. However, because halogenic elements are not homopolymerizable, carbon (EA = −122 kJ/mol)-based polymers (i.e. PTFE, PVDF) are often employed for structural use and mechanical integrity at the expense of reduced electron affinity, intrinsically sacrificing triboelectric energy harvesting. Herein, we report the first example of triboelectric energy harvesting with sulfur backbone-based inorganic polymers synthesized via inverse-vulcanization process of elemental sulfur, a by-product of petroleum refining process. Fluorinated polymeric sulfur demonstrated 6-fold and 3-fold increase in triboelectric energy outputs in voltage and currents respectively in comparison with commercial PTFE film. Such high energy harvesting was achieved by high electron affinity of sulfur (−200 kJ/mol) and by its hypervalency via expanded-octet which provided coordination of two additional bonds with halogens compared to carbon. The triboelectric open-circuit voltage output reached 1366 V and demonstrated direct powering of 630 LEDs under the minimal force of ~30 N. This yellow chemistry-based molecular engineering paves a way for a new class of triboelectric materials toward low-cost, eco-friendly, and scalable triboelectric energy harvesting applications.

Controlling polymer properties through the shape of the molecular-weight distribution

The manipulation of a polymer’s properties without altering its chemical composition is a major challenge in polymer chemistry, materials science and engineering. Although variables such as chemical structure, branching, molecular weight and dispersity are routinely used to control the architecture and physical properties of polymers, little attention is given to the often profound effect of the breadth and shape of the molecular-weight distribution (MWD) on the properties of polymers. Synthetic strategies now make it possible to explore the importance of parameters such as skew and the higher moments of the MWD function beyond the average and standard deviation. In this Review, we describe early accounts of the effect of MWD shape on polymer properties; discuss synthetic strategies for controlling MWD shape; describe current endeavours to understand the influence of MWD shape on rheological and mechanical properties and phase behaviour; and provide insight into the future of using MWDs in the design of polymeric materials. Controlling polymerization is required to fully understand and tune the function of a polymer. Alongside variables such as dispersity, molecular weight and chemical composition, the shape of the molecular-weight distribution has substantial influence on polymer properties. In this Review, we discuss methods to systematically control the shape of a polymer’s molecular-weight distribution, as well as explore the profound effects of shape on polymer properties.

Resilience to Conformational Fluctuations Controls Energetic Disorder in Conjugated Polymer Materials: Insights from Atomistic Simulations

Increasing the crystallinity of thin films in concert with the planarization of the conjugated backbones has long been considered as the key for success in the design of polymer materials with opti...

Computer-aided design of polymeric materials: Computational study for characterization of databases for prediction of mechanical properties under polydispersity

In Polymer Informatics, quantitative structure-property relationship (QSPR) modeling is an emerging approach for predicting relevant properties of polymers in the context of computer-aided design of industrial materials. Nevertheless, most QSPR models available in the literature use simplistic computational representations of polymers based on their structural repetitive unit. The aim of this work is to evaluate the effect of this simplification and to analyze new strategies to achieve alternative characterizations that capture the phenomenon of polydispersity. In particular, the experiments reported in this work are focused on three mechanical properties derived from the tensile test. The reported results revealed the disadvantages of using these simplified representations. Besides, we contributed with alternative representations for the databases of polymer molecular descriptors that achieved more realistic and accurate QSPR models.

Designing polymers for advanced battery chemistries

Electrochemical energy storage devices are becoming increasingly important to our global society, and polymer materials are key components of these devices. As the demand for high-energy density devices increases, innovative new materials that build on the fundamental understanding of physical phenomena and structure–property relationships will be required to enable high-capacity next-generation battery chemistries. In this Review, we discuss core polymer science principles that are used to facilitate progress in battery materials development. Specifically, we discuss the design of polymeric materials for desired mechanical properties, increased ionic and electronic conductivity and specific chemical interactions. We also discuss how polymer materials have been designed to create stable artificial interfaces and improve battery safety. The focus is on these design principles applied to advanced silicon, lithium-metal and sulfur battery chemistries. Polymers are ubiquitous in batteries as binders, separators, electrolytes and electrode coatings. In this Review, we discuss the principles underlying the design of polymers with advanced functionalities to enable progress in battery engineering, with a specific focus on silicon, lithium-metal and sulfur battery chemistries.

Monomer Design of Polymer Materials with High RefractiveIndex and High Glass Transition Temperature

Monomer Design of Polymer Materials with High RefractiveIndex and High Glass Transition Temperature

Controlling the degradation of an oxidized dextran-based hydrogel independent of the mechanical properties

The objective of this study is to control and elucidate the mechanism of molecular degradation in a polysaccharide hydrogel. Glycidyl methacrylate (GMA) immobilized dextran (Dex-GMA) was oxidized by periodate to introduce aldehyde groups (oxidized Dex-GMA). The hydrogel was formed by the addition of dithiothreitol to the oxidized Dex-GMA solution through thiol Michael addition with the preservation of the aldehyde group for degradation points. It was experimentally determined that the degradation of this hydrogel can be controlled by the addition of amino groups and the speed of degradation can be controlled independently of mechanical properties because crosslinking and degradation points are different. In addition, the molecular mechanism of the crosslinking between the thiol and aldehyde groups was found to control the degradation of dextran derivatives. It is expected that these results will be beneficial in the design of polymer materials in which the speed of degradation can be precisely controlled. In addition, the cytotoxicity of oxidized Dex-GMA was approximately 3000 times lower than that of glutaraldehyde. The low cytotoxicity of the aldehyde in oxidized Dex-GMA was the likely reason for the harmless functionalized polysaccharide material. Possible future clinical applications include cell scaffolds in regenerative medicine and carriers for drug delivery systems.

Computational Design of Photocured Polymers Using Stochastic Reaction–Diffusion Simulation

AbstractPhotopolymerization is widely used for creating materials for biomedical applications, lithography, and fast 3D fabrication. The resin composition and curing protocol during polymerization define a high‐dimensional parameter space that dictates the reaction kinetics, network structures, and physical properties of polymerized materials. But a quantitative map from the input parameter space to the transient and final properties does not exist. Here, a computational method is presented to simulate network growth as a stochastic process using reaction‐diffusion master equations. The evolving diffusivity of reacting species during polymerization is modeled using effective medium method, thereby making the rates of reaction and fluctuation events sensitive to the spatial configuration of a growing network. The numerical studies show that this method can correlate fabrication parameters to polymer properties like crosslink heterogeneity, relaxation time, phonon density of states, and bulk modulus, in silico. Hence, stochastic simulation of polymerization is broadly applicable to accelerate the design of polymeric materials with targeted physical properties for specific applications.

Microwave-Assisted Synthesis of Sucrose Polyurethanes and Their Semi-interpenetrating Polymer Networks with Polycaprolactone and Soybean Oil

Because of the current interest in sustainability, environmental stewardship, and green chemistry, there has been a lot of interest in using agro-based raw materials for the design of polymeric materials. One of the promising biorenewable materials is sucrose, which is inexpensive and widely available. In this work we have carried out the synthesis of sucrose–toluene diisocyanate-based polyurethane through microwave-assisted reactions. Comparisons of conventional heat versus microwave reactions have been made. Microwave-assisted synthesis has been found to significantly decrease the reaction time and save energy relative to conventional heat. The sucrose polyurethane has turned out to be a suitable matrix to prepare semi-interpenetrating polymer networks (semi-IPNs) involving a second material. Two examples shown in this work are the semi-IPNs of sucrose polyurethane with polycaprolactone and soybean oil. Characterization of the polymers has been conducted with 13C NMR, FT-IR, size-exclusion chromatograph...