Synthesis Of Polymeric Materials Research Articles

Flame Retardancy and Thermal Stability of Rigid Polyurethane Foams Filled with Walnut Shells and Mineral Fillers.

Recently, the influence of the concept of environmental sustainability has increased, which includes environmentally friendly measures related to reducing the consumption of petrochemical fuels and converting post-production feedstocks into raw materials for the synthesis of polymeric materials, the addition of which would improve the performance of the final product. In this regard, the development of bio-based polyurethane foams can be carried out by, among other things, modifying polyurethane foams with vegetable or waste fillers. This paper investigates the possibility of using walnut shells (WS) and the mineral fillers vermiculite (V) and perlite (P) as a flame retardant to increase fire safety and thermal stability at higher temperatures. The effects of the fillers in amounts of 10 wt.% on selected properties of the polyurethane composites, such as rheological properties (dynamic viscosity and processing times), mechanical properties (compressive strength, flexural strength, and hardness), insulating properties (thermal conductivity), and flame retardant properties (e.g., ignition time, limiting oxygen index, and peak heat release) were investigated. It has been shown that polyurethane foams containing fillers have better performance properties compared to unmodified polyurethane foams.

Hybrid deterministic and stochastic approach for dynamic simulation of photoinduced atom-transfer radical polymerization processes with microscopic resolution

Among the various polymerization mechanisms available for producing polymers, photoinduced atom-transfer radical polymerization (photoATRP) stands out as a promising technique. By utilizing light as an external stimulus, photoATRP facilitates the production of well-defined polymers with precise distributions. The demand for advanced polymeric materials synthesis necessitates a deep understanding of polymer chains at the molecular level. As molecular weight distribution (MWD) is a key quality index of polymers, developing models with embedded MWD information holds significance for process design and optimization tasks. In this work, an accelerated hybrid deterministic and stochastic approach is proposed for simulating dynamic photoATRP processes. The proposed approach demonstrates computational efficiency and flexibility, enabling precise predictions for the evolution of both macroscopic and microscopic properties of polymers. An application to a batch photoATRP system model is presented to illustrate the validity and performance of the proposed hybrid approach.

Non-isocyanate polyurethanes synthesized from terpenes using thiourea organocatalysis and thiol-ene-chemistry

The depletion of fossil resources as well as environmental concerns contribute to an increasing focus on finding more sustainable approaches for the synthesis of polymeric materials. In this work, a synthesis route towards non-isocyanate polyurethanes (NIPUs) using renewable starting materials is presented. Based on the terpenes limonene and carvone as renewable resources, five-membered cyclic carbonates are synthesized and ring-opened with allylamine, using thiourea compounds as benign and efficient organocatalysts. Thus, five renewable AA monomers are obtained, bearing one or two urethane units. Taking advantage of the terminal double bonds of these AA monomers, step-growth thiol-ene polymerization is performed using different dithiols, to yield NIPUs with molecular weights of above 10 kDa under mild conditions. Variation of the dithiol and amine leads to polymers with different properties, with Mn of up to 31 kDa and Tg’s ranging from 1 to 29 °C.

Hydrogel Assisted Synthesis of Polymeric Materials Based on Chitosan, Oxidized Pectin, and Tantalum MOF Nanostructures as Potent Antibiotic Agents Against Common Pathogenic Strains Between Humans and Aquatic

Hydrogel Assisted Synthesis of Polymeric Materials Based on Chitosan, Oxidized Pectin, and Tantalum MOF Nanostructures as Potent Antibiotic Agents Against Common Pathogenic Strains Between Humans and Aquatic

Direct observation of radiation-induced graft polymerization on a polyethylene film

Radiation-induced graft polymerization is widely used in the synthesis of polymeric materials with various functionalities; however, the details of the reaction mechanism are still unresolved. Herein, the initial stage of the graft polymerization reaction was investigated through atomic force microscopy (AFM). We used glycidyl methacrylate (GMA) in methanol (monomer solution) and a high-density polyethylene (HDPE) film with a well-ordered lamellar structure as the substrate. Using polymer film surfaces with a maximum grafting degree of 0.5%, AFM can distinguish between crystalline and amorphous polyethylene (PE) phases as well as a grafted polymer GMA (PGMA) phase. The graft polymerization reaction started from the interface between the crystalline and amorphous PE phases. As the reaction proceeded, the PGMA covered the crystalline PE phase: i.e., the entire surface of the PE film were covered by the PGMA. Further, the crystalline lamellae of the PE film eventually became a scaffold for the formation of aggregates comprising grafted polymer chains alone. The graft polymerization reaction mechanism was explained by comparing the solubility parameters of the monomer solution, substrate, and grafted polymer chains. Understanding the reaction mechanism at a low grafting degree obtained in this study may contribute to enhancing the efficiency of the graft polymerization reaction on any polymeric material.

Employment and performance of modified chitosan for the removal of copper ions and methylene blue in wastewater

AbstractExploring new and efficient adsorbents for the purification of water from heavy metals and organic waste to provide clean drinking water is highly demanded. Herein, the synthesis of polymeric materials based on grafting chitosan (Cs) by various acrylic monomers as acrylic acid (AA), 2‐acrylamide‐2‐methyl propane sulfonic acid (AMPS), and acrylamide (Am) namely S1, S2, or S3, respectively, using methylene bisacrylamide (NMBAm) as crosslinker was performed. The formed polymeric compound was characterized by utilizing Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X‐ray, and Brunauer–Emmett–Teller. It was determined that S2 possessed a higher specific surface area of 109.133 m2/g, which is higher than S1 (71.2553 m2/g) and S3 (62.8847 m2/g). The as‐prepared polymeric compounds were utilized for the removal of copper ions (Cu2+) and methylene blue (MB) from wastewater in the absence and presence of UV light irradiation. The kinetic study and the adsorption isotherms for the removal of Cu2+ and MB as organic pollutants using the as‐prepared polymeric compound were studied.

Fabrication and characterization of poly(tannic acid) coated magnetic clay decorated with cobalt nanoparticles for NaBH4 hydrolysis: RSM-CCD based modeling and optimization

Hydrogen generation from sodium borohydride (NaBH4) hydrolysis in the presence of metal catalysts is a frequently used and encouraging method for hydrogen storage. Metal nanoparticle-supported catalysts are better recyclability and dispersion than unsupported metal catalysts. In this study, the synthesis and characterization of a polymer-supported catalyst for hydrogen generation using NaBH4 have been investigated. For the synthesis of polymeric material, first of all, kaolin (KLN) clay has been magnetically rendered by using the co-precipitation method (Fe3O4@KLN) and then coated with poly tannic acid (PTA@Fe3O4@KLN). Then, the catalyst loaded with cobalt (Co) nanoparticles have been obtained with the NaBH4 reduction method (Co@PTA@Fe3O4@KLN). The surface morphology and structural properties of the prepared catalysts have been determined using methods such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICP-MS) and vibrating sample magnetometer (VSM). The optimization of the most important variables (NaBH4 amount, NaOH amount, catalyst amount, and metal loading rate) affecting the hydrolysis of NaBH4 using the synthesized polymeric catalysts was carried out using response surface methodology (RSM). Depending on the evaluated parameters, the desired response was determined to be hydrogen production rate (HGR, mL/g min). HGR was 1540.4 mL/gcat. min. in the presence of the Co@PTA@Fe3O4@KLN at optimum points obtained via RSM (NaBH4 amount 0.34 M, NaOH amount 7.9 wt%, catalyst amount 3.84 mg/mL, and Co loading rate 6.1%). The reusability performance of the catalyst used in hydrolysis of NaBH4 was investigated under optimum conditions. It was concluded that the catalyst is quite stable.

Facile Approach for the Synthesis of Performance-Advantaged Degradable Bio-Based Thermoset via Ring-Opening Metathesis Polymerization from Epoxidized Soybean Oil

Design and synthesis of polymeric materials from sustainable feedstocks can partly mitigate environmental polymer pollution, and hence, it has received constant attention. This work aims to synthesize a degradable bio-based thermoset via ring-opening metathesis polymerization (ROMP) from epoxidized soybean oil (ESO). ESO was converted to norbornene-functionalized ESO first, and then, this functionalized ESO was rapidly generated to a thermoset via ROMP. The ESO-based thermoset exhibits promising thermal properties and mechanical performance, is available for fabrication of composites, and can be fully degraded into small molecules and oligomeric species under aqueous NaOH or KOH. Moreover, the functionalized ESO can copolymerize with norbornene to form partially degradable copolymers. This approach can be used to synthesize degradable vegetable oil-based thermosets for various applications and for environmental sustainability.

Flame Retardant Waterborne Polyurethanes: Related Analytical Measurements

Flame-retardant waterborne polyurethane has long been studied as a flame-retardant, non-flammable, adhesive material for wood, for example. Since there are already many good review articles and specialized books, this chapter will review only the major studies of new flame-retardant aqueous polyurethanes reported in the last few years. In many cases, there is the synthesis of polymer materials, thermal analysis that proves flame retardancy alone or in combination with other materials, as well as FTIR, NMR, MS for structural confirmation, and SEM for aggregate state confirmation. The study may be carried out by several measurements such as EDX analysis. On the other hand, material flammability tests may include limiting oxygen index, vertical combustion, and cone calorimeter tests. This chapter focuses on methods of analytical measurement of flammability, the purpose of these methods, the correlation between flame retardancy and other structures/physical properties, and related experiments and discussions including composite/special measurements such as TGA-FTIR, and in situ FTIR. Additionally, the authors would like to summarize the relationship between analytical measurements such as thermal measurement with other applications such as macromolecules for photochromic and fluorescence.

Microdroplet-Mediated Radical Polymerization.

Micrometer-sized aqueous droplets serve as a unique reactor that drives various chemical reactions not seen in bulk solutions. However, their utilization has been limited to the synthesis of low molecular weight products at low reactant concentrations (nM to μM). Moreover, the nature of chemical reactions occurring outside the droplet remains unknown. This study demonstrated that oil-confined aqueous microdroplets continuously generated hydroxyl radicals near the interface and enabled the synthesis of polymers at high reactant concentrations (mM to M), thus successfully converting the interfacial energy into the synthesis of polymeric materials. The polymerized products maintained the properties of controlled radical polymerization, and a triblock copolymer with tapered interfaces was prepared by the sequential addition of different monomers into the aqueous microdroplets. Furthermore, a polymerization reaction in the continuous oil phase was effectively achieved by the transport of the hydroxyl radicals through the oil/water interface. This interfacial phenomenon is also successfully applied to the chain extension of a hydrophilic polymer with an oil-soluble monomer across the microdroplet interface. Our comprehensive study of radical polymerization using compartmentalization in microdroplets is expected to have important implications for the emerging field of microdroplet chemistry and polymerization in cellular biochemistry without any invasive chemical initiators.

Pineapple Fiber Hybrids Prepared by the Fusion of radiation-induced Graft Polymerization and Kabachnik-Fields three-component Reaction (RIGP-KF3CR)

ABSTRACT The fusion of multicomponent reactions and polymer chemistry allows the synthesis of polymeric materials that contain special classes of molecules that are otherwise difficult to produce. In this study, a locally available nonwoven fabric composed of pineapple fibers and polylactic acid (piñatex) was modified by radiation-induced graft polymerization (RIGP) of vanillin methacrylate, a lignin-derived monomer. RIGP yielded organic hybrids made from a natural, renewable, and biodegradable substrate, and surface aldehyde groups from vanillin. The grafted fabric was prepared by gamma pre-irradiation at 50 kGy, exhibiting an increasing degree of grafting with increasing reaction time and monomer concentration. Post-polymerization modification carried out using Kabachnik-Fields three-component reaction (KF3CR) enabled the immobilization of amine and phosphite moieties on the fabric. FTIR, SEM-EDS and XPS analysis of 8 amine and phosphite combinations showed the presence of the corresponding elements and functional groups, indicating successful surface functionalization through RIGP-KF3CR. All modified natural fibers-based fabrics displayed enhanced thermal stability without obvious radiation degradation effects. Synthesized natural fibers contain α-aminophosphonate pendants which may be useful in the selective adsorption and recovery of industry valuable metals.

Organosilicone Compounds in Supercritical Carbon Dioxide.

This review considers the key advantages of using supercritical carbon dioxide as a solvent for systems with organosilicon compounds. Organosilicon polymeric materials synthesis as well as the creation and modification of composites based on them are discussed. Polydimethylsiloxane and analogues used as polymerization stabilizers and nucleation promoters in pore formation processes are analyzed as well.

Recent developments of Madhuca indica (Mahua) oil-based polymers: A mini review

Nowadays, the use of non-edible vegetable oils as the raw material for polymer development is growing in interest because of the scarcity and high demand for crude oil and also because of its eco-friendly approach. The utilization of non-edible oil to synthesize the applicable polymers reduces the usage of petrochemicals. To eliminate the reliance on petrochemicals, it is important to search for and extract alternate and domestic non-edible oils suitable for the synthesis of polymeric materials. This is now a promising research approach. The outstanding feature of indigenous, non-edible Madhuca indica oil (MO) is its chemical structure, with unsaturated sites and esters that are considerable ingredient polyols for the development of polymers. This review discusses the origin, structure and extraction of MO and systematically focuses on the recently developed polymers using oil as a renewable source of polyols. We have briefly reviewed MO-based polymeric materials such as alkyd resins like pentaalkyds for scratch resistance, glycerol alkyds for fly-ash coating, pentalkyd LC resins for display coating applications and epoxies of MO for biological coating materials. Also, the important polyurethanes in the pathways of MO-based fatty amide are transformed into the polyetherimide polyols through a step-growth reaction with bisphenol-A or bisphenol derivatives, which again react with isocyanates to produce MO-based PU for excellent adhesion and coating applications. Another type of waterborne polyurethane is made from polyesteramides. These PU coatings are used in the paint and pigment industries. We reviewed their synthesis and widespread use in coatings and composites.

Measurement and Dynamic Modeling of Hydrogen Separation from Hydrogen Enriched Natural Gas Using Phosphoric Acid Doped Polybenzimidazole Hydrogen Pump

The blending of hydrogen into pre-existing natural gas pipelines as a means of transporting hydrogen to consumers is an attractive strategy with regards to cost and efficiency [1]. In many jurisdictions hydrogen blending has been determined to be technically feasible today when considering concentrations of hydrogen up to 15-20% by volume [2]. Fuel cell electric vehicle fueling, among other desirable hydrogen end-uses, requires high-purity hydrogen feedstock and thus the capability to efficiently extract high purity hydrogen from hydrogen blended natural gas is identified as a critical component in adopting hydrogen natural gas blends as an energy transition strategy [3].Proton-conducting membranes can be utilized to separate hydrogen electrolytically from blended gas streams efficiently while producing a high purity product. Perfluorosulfonic acid (PFSA) membranes such as Nafion are the most employed due to their high proton conductivity as well as their high mechanical strength but are complicated by the need for membrane humidification. High-temperature proton exchange membranes (HT-PEM) offer attractive characteristics relative to the PFSA-based cells, particularly in their application to hydrogen separation. Phosphoric-acid (PA) doped polybenzimidazole (PBI) membranes have high proton conductivity at temperatures of 160oC without the presence of water and due to these higher operating temperatures have improved reaction kinetics and catalyst tolerance to impurities such as CO and sulfur. Their ability to separate hydrogen from nitrogen, CO2, and low concentrations of CO (~1% vol) was shown by Perry et al. [4]. Recent developments in PA-doped polymeric materials synthesis has led to improved durability and performance [5] and even higher operating temperatures offering further performance benefits [6].This study examines the use of a single cell HT-PEM H2 pump based on PA-doped PBI membrane for the separation of hydrogen from hydrogen blended methane and natural gas. The experiments are performed on 5 cm2 cells with in-house gas diffusion electrodes. Freudenberg H23C2 is used as a gas diffusion layer. The catalyst layer consists of PTFE binder and 40% wt Pt/C catalyst with loading of 1 mg Pt/cm2 . The PBI membranes (Fumapem AP-30) are soaked in 85%wt H3PO4 at room temperature for 2 days. Hydrogen concentration in the feed gas (2-20% molar concentration), hydrogen recovery rate, and other operating conditions are varied to characterize cell performance in terms of hydrogen separation efficiency. We show a feasibility to separate hydrogen from various blends from 20% down to 2 % molar concentration (Figure 1). For the most constrained case of 2 % H2 in methane an overpotential of 240 mV at 0.2 A/cm2 was observed. Gas chromatography is used to provide outlet gas composition. Electrochemical measurements from cell operation are used to modify and validate existing 2-D non-isothermal dynamic PEM cell model [7].

Amphiphilic Asymmetric Diblock Copolymer with pH-Responsive Fluorescent Properties.

Stimuli-responsive polymers with changeable fluorescent properties have numerous applications in sensing, bioimaging, and detection. Here we describe the facile synthesis of a pH-responsive amphiphilic asymmetric diblock copolymer of acrylic acid and butyl acrylate that incorporates a polarity-sensitive fluorophore. The asymmetric structure enhances the stimuli-responsive behavior: as the environmental pH decreases, the fluorescent intensity of the asymmetric diblock copolymer gradually increases, whereas its symmetric block counterpart shows limited and stepwise change. Besides, this remarkable difference was demonstrated to be concentration-independent, as similar emission behavior was found for both polymers at lower concentrations. These results indicate that the fluorescence properties of the copolymer can be adjusted by rationally designing the copolymer structure. This work provides a novel and general strategy for the design and synthesis of polymeric materials with encapsulated structures showing stimuli-responsive fluorescent properties to be applied as fluorescent probes with a smoothly varying response curve rather than the simple on-off switch that is typical of block copolymer systems.

Effect of cell culture media on photopolymerizations.

Radical polymerization is one of the most widely used methods for the synthesis of polymeric materials for biomedical applications, such as drug delivery, 3D cell culture, and regenerative medicine. Among radical polymerization reactions, thiol-ene click chemistry has shown excellent orthogonality in diverse reaction conditions. However, our preliminary investigations revealed that it fails in cell culture environment. Herein, we investigate the mechanisms by which cell culture media interfere with radical photoreactions. Three different models including free radical linear photopolymerization (N,N-dimethylacrylamide photopolymerization), free radical photohydrogelation (poly(ethylene glycol) diacrylate photohydrogelation), and thiol-ene photohydrogelation (4-arm poly(ethylene glycol)-norbornene thiol-ene photohydrogelation) were investigated. We showed that common cell culture media ingredients can interfere with radical polymerization by two different pathways; namely, radical chain transfer and radical scavenging effects. Thiol-ene photoclick hydrogelation was seriously affected by cell culture media especially under the alkaline conditions of many of them, due to the impact of deprotonation of the thiol reactant. We intend these findings to serve as a reference guide to researchers employing free radical-based molecular synthesis in cell culture settings. The nonbenign impact of media components, pH, and concentration should provide a cue for future studies that aim to prepare well-defined polymeric materials in the presence of cell culture media.

Terpolymerization of CO2 with Epoxides and Cyclic Organic Anhydrides or Cyclic Esters

The synthesis of polymeric materials starting from CO2 as a feedstock is an active task of research. In particular, the copolymerization of CO2 with epoxides via ring-opening copolymerization (ROCOP) offers a simple, efficient route to synthesize aliphatic polycarbonates (APC). In many cases, APC display poor physical and chemical properties, limiting their range of application. The terpolymerization of CO2 with epoxides and organic anhydrides or cyclic esters offers the possibility, combining the ROCOP with ring-opening polymerization (ROP), to access a wide range of materials containing polycarbonate and polyester segments along the polymer chain, showing enhanced properties with respect to the simple APC. This review will cover the last advancements in the field, evidencing the crucial role of the catalytic system in determining the microstructural features of the final polymer.

Bio-based polyamide

Abstract Biobased polymers are sustainable polymers produced from renewable resources such as biomass feedstocks instead of the industrial fossil resources such as petroleum and natural gases. This trend helps in creating an environmentally friendly chemical processing that is characterized by low carbon footprint emission to the globe which in turn will limit the increase of the atmospheric carbon dioxide concentration even after their incineration. Synthesis of polymeric materials from biobased resources also solves the problem of polymer waste recycling. This chapter covers a basic background on the origin and importance of biobased polyamides, different synthetic routes of their starting monomeric materials obtained from biomass feedstocks, and a brief summary of the physical and chemical properties and applications of some common aliphatic, semiaromatic and fully aromatic polyamides. This chapter ends with a recent published data on the growth of the global market of biobased polyamides to emphasize on the economic importance of this manufacturing trend.

Liquid Phase Electron Microscopy Provides Opportunities in Polymer Synthesis and Manufacturing

Liquid phase electron microscopy (LP-EM) is a rapidly developing method for imaging chemical processes in solution. A key strength of this method is that the high energy electrons can be used as both an energy and illumination source. This enables simultaneous control of the chemistry with nanoscale structural characterization. As electron beams are widely used in the manufacturing of polymeric materials, we believe that the knowledge obtained from LP-EM can directly guide industrial electron beam technologies, enabling the design, optimization, and manufacturing of nanostructured polymeric materials. In this Perspective, we outline the advances made in electron beam synthesis of polymeric materials and discuss the challenges and opportunities for utilizing LP-EM in conjunction with electron beam manufacturing technologies.

Synthesis and Thermo-Mechanical Study of Epoxy Resin-Based Composites with Waste Fibers of Hemp as an Eco-Friendly Filler.

The synthesis, thermal, and mechanical properties of epoxy resin composites incorporating waste fibers of hemp were studied. Five different systems with increasing quantity of the eco-filler were obtained. For the synthesis of polymeric materials, the commercial epoxy resins Epidian® 5 and triethylenetetramine (TETA) were applied as crosslinking agents. The composites were obtained based on the polyaddition reaction of an amine group with an epoxide ring. ATR/FT-IR (Attenuated Total Reflection-Fourier Transform Infrared) analysis was used to confirm the chemical structure of the composites and the course of curing processes. Moreover, the influence of the eco-friendly components on the mechanical properties was determined, while thermal properties of the materials were investigated by thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC). Dynamic mechanical studies (DMA) and Shore hardness tests of the obtained polymers were also carried out. The DSC curves and DMA analysis revealed that all materials were characterized by a similar glass transition range. Furthermore, the DMA and hardness measurements of the composites demonstrated an increasing elasticity with the increase in the amount of eco-filler present in the compositions.