Use Of Polymers Research Articles

Encapsulation of hemoglobin within mPEG-b-PCL micelle for development of artificial oxygen carrier

The aim of this study is to develop hemoglobin (hb) encapsulated self-assembled polymer for use as artificial oxygen carrier. Methoxy-polyethylene glycol (mPEG45) block and poly (ɛ-caprolactone [ɛ-CL]) (mPEG-b-PCL) that formed diblock copolymer was synthesized via ring-opening polymerization (ROP). Extracted and purified hb was then encapsulated in polymer with critical micelle concentration (CMC) at 1.0–2.0 mg/mL. Average encapsulation efficiency of the human hb-micelle was 45 ± 5% as compared to 66.7 ± 15% of bovine hb-micelle. The derived half-life of hb encapsulated micelle was 112,242 ± 40 min upon atmospheric air exposure as compared to 30 ± 10 min of the experiment control (free hb). Results of oxygen reversibility study also demonstrated the capability of hb-micelle to endure minimum average of six oxygenation and deoxygenation cycles as compared to an average less than one average cycle by the control. Control (free bovine and human hb) and treated cell (bovine and human hb-micelle) were incubated for 48 h and analyzed every 4, 8, 12, 16, 24, and 48 h. Cell viability assay on macrophage cell demonstrated both free hb(s) recorded decreasing cell growths as early as 8 h as compared to the increasing cell viability pattern by the encapsulated hb(s) indicating lesser cytotoxicity.

Manipulation of aggregation-induced emission of thermoresponsive fluorescent polymers having Au(I)–S groups for a fluorescent chemosensor

Aggregation-induced emission (AIE) is a new technique for enhancing fluorescence. To demonstrate manipulation of near-infrared AIE by thermal stimuli for analytical use, we synthesized a thermoresponsive fluorescent polymer containing Au(I)–S bonds as near infrared fluorophores. We also examined the polymer for use as a fluorescent chemosensor based on the manipulation of AIE. The thermoresponsive fluorescent polymer was prepared from poly(N-isopropylacrylamide-co-methacrylic acid) by introducing thiol groups which were further modified to form fluorescent Au(I)–S bonds. The thermoresponsive fluorescent polymer aggregated and then fluoresced in the near infrared region due to AIE when heated above the phase transition temperature of 32 °C. The change in fluorescence intensity of the polymer was reversible by changing the solution temperature. Because the residual carboxyl groups make the thermoresponsive fluorescent polymer negatively ionizable, neutralization by the addition of positively charged analytes facilitates its aggregation to enhance fluorescence above the phase transition temperature. When hemoglobin, which has an isoelectric point of 6.8, was added to a pH 6.0 polymer solution at 40 °C, the polymer aggregated to enhance its fluorescence as a result of neutralization. A linear relationship between the hemoglobin concentration and the fluorescence intensity of the polymer was obtained for 0.5–2.0 g/L hemoglobin with a detection limit (3 s) of 0.014 g/L.

Tuning the performance of pyrido[4,3-b]pyrazine-EDOT hybrid polymers for use as neutral green electrochromic materials

Tuning the performance of pyrido[4,3-b]pyrazine-EDOT hybrid polymers for use as neutral green electrochromic materials

Poly(lactic acid)-PLA: An Analysis Based on Literature Text Mining

The most researched and used biodegradable aliphatic polyester worldwide is poly (lactic acid) - PLA. Due to its inherent properties, PLA is a leading biomaterial for several and numerous applications and the most promising biopolymer capable of replacing conventional petroleum-derived polymers. Besides, PLA is also one of the most promising candidates for new developments in the traditional sectors such as packaging and the automotive industry, in the electronics industry, and the biomedical area. To verify the importance of drug release in the various applications of PLA, a text mining of the last ten years was carried out. The text-mining tool was used to identify this polymer's main applications in the last ten years, allowing us to draw a map year by year based on correlation analysis. Firstly, an analysis was made of the main applications of PLA in scientific research, by searching for "PLA", in the ScienceDirect scientific base (https://www.sciencedirect.com/) and using the online tool Voyant Tools. Some words related to drug release were selected, checking how many times they were mentioned over the years. In this way, it was possible to see which years were the most and least used PLA in drug release. It was not possible to observe a gradual increase or decrease in this polymer's use, for this purpose, over time. The text mining presented here proved to be an efficient and fast way to observe the desired theme.

Synthesis and Performance Evaluation of Green Anionic Polymeric Surfactant for Detergent Application

The main role of this study is to prepare the green polymer based anionic surfactant as an alternative to non-biodegradable surfactant for detergent applications. The detergent properties i.e., surface tension measurements, foaming property, emulsifying ability, dispersing property, FTIR analysis and wetting behaviour were studied using several rheological techniques. The critical micelle concentration (CMC) value was obtained at 6 mg/L of surfactant concentration showing no further remarkable changes in surface tension with increases in concentration. Low surface tension value was correlated with decrease in cohesive force exist between the molecules and allowed the surfactant easily adsorbed on the pore surface. The low surface tension value, reliable wetting characteristic, excellent emulsifying power, benchmark dispersing behaviour and suitable foaming property assuring the successful utilization of polymer based anionic surfactant for detergent applications

In Situ Polymerization of Chiral Poly(fluorene-alt-benzothiadiazole) Nanocomposites with Enhanced Chirality

Poly(fluorene-alt-benzothiadiazole) (PFBT) is a promising chiral polymer for use in metamaterials and other photonic applications, due to its large chiral optical activity at visible wavelengths. However, its usages are very limited, since it is not readily patternable into microstructures and challenging to apply to applications. In this paper, we demonstrate photo patterning of chiral PFBT/Achiral SU-8 photoresist to produce high quality structures while retaining the extraordinary chiral optical activity of our previously-reported PFBT/SU8 nanocomposite films. The ability to produce cleanly patterned microfeatures with high chirality may enable wider use of PFBT in chiral metamaterials and other photonic applications.

An investigation on the potential of bio-based polymers for use in polymer gear transmissions

The potential for replacing the fossil-based Polyoxymethylene (POM) and Polyamide 66 (PA 66) in polymer gear applications with a bio-based Polyamide 6.10 (PA 6.10) was studied and is presented in the article. The use of bio-based plastics is increasing but mostly in undemanding applications like packaging. High-performance plastics are needed in polymer gear transmissions since their operational conditions are far more severe. The potential of bio-based PA 6.10 was studied by means of gear lifespan testing. Additional insights into the process of polymer gear meshing were garnered by simulating all the tested cases with a FEM model of meshing gears. Test gears were manufactured from commercially available materials, making the results useful for gear designers. Encouraging results were observed since the PA 6.10 gears exhibited a 3.5-times longer lifespan than POM gears and a 10-times longer lifespan than PA 66 gears when tested under identical test conditions. The results indicate great potential for replacing fossil-based plastics in polymer gear applications with bio-based polymer materials. The fatigue strength, coefficient of friction, and wear coefficient were determined and compared for the tested materials, facilitating the reliable design of polymer gears.

Rapid preparation of 1-vinylimidazole based non-affinity polymers for the highly-selective purification of antibodies from multiple biological sources

There is an urgent need for developing advanced purification techniques with the merits of low cost and satisfactory capacity in order to meet the challenges in the current downstream purification of monoclonal antibodies (mAbs). Herein, a simple and inexpensive nitrogen heterocycle molecule, 1-vinylimidazole (VIM), was proposed as the capture ligand of antibodies for the first time. The corresponding VIM-based non-affinity polymeric material (polyVIM) was then fabricated via a one-step polymerization for use in the highly selective purification of antibodies. Compared to the previously reported materials, this novel material exhibited many advantages without clearly sacrificing selectivity, such as a simpler and faster fabrication (within 1.5 h), comparable or even higher binding capacity (saturated static adsorption capacity > 190 mg/g polymer, dynamic binding capacity about 31.62 mg/g polymer), lower non-specific protein adsorption, and much lower cost. Notably, the polyVIM can effectively purify the antibodies from multiple biological sources with high purity (95.4% for mAbs in the cell culture medium, 93.3% for hIgG in the human serum), with an acceptable recovery (91.6% for mAbs, 77.0% for hIgG), and good reusability (> 10 times). Moreover, the target ELISA binding assay and NFAT-luc reporter gene assay demonstrated that the enriched antibodies can well maintain their binding activity and bioactivity during the whole purification process. The excellent performance of the polyVIM material may be attributed to the high recognition ability of VIM for antibodies, as well as the biocompatible and antifouling properties of the porous polymer. This study provides a promising alternative material for the purification of mAbs in downstream processes and the enrichment of hIgG in human serum.

Characterization and likelihood application of extracted mucilage from Hollyhocks plant as a natural polymer in enhanced oil recovery process by alkali-surfactant-polymer (ASP) slug injection into sandstone oil reservoirs

Injection of water-based polymeric solutions into oil reservoirs is a common way to enhance oil recovery in the tertiary oil production stage. Polymers are normally injected under different scenarios individually, or with surfactants and alkalis, or both as a slug. Adjusting the ratio of water and oil mobility, preventing the phenomenon of fingering and early production of injectable water by increasing water viscosity are the most important mechanisms of polymer injection in enhanced oil recovery (EOR) process. In this study, the possibility of using extracted mucilage from Hollyhocks plant as a natural polymer for injection as a slug with surfactant and alkaline in sandstone reservoirs was investigated. The plant polymer was characterized by Fourier Transform Infrared Spectroscopy (FTIR), Energy Dispersive X-ray Analysis (EDAX) and Thermal Gravimetric Analysis (TGA) after extraction and preparation. Viscosity tests were performed at different shear rates and the effects of polymer concentration, polymer hydration time, temperature and salinity on the viscosity of the polymeric solutions were investigated. Finally, a polymeric slug containing the polymer, an anionic surfactant at the critical concentration of micelle (CMC) and NaOH alkali at the optimum concentration was injected into a sandstone plug to calculate the oil recovery rate by the Alkali-Surfactant-Polymer (ASP) slug injection process. The novelty of this research is the introduction and use of a new, affordable and inexpensive polymer for use in ASP-slug injection into sandstone reservoirs, which can solve many of the challenges in this method. Based on the results, TGA analysis confirms the stability of the polymer at reservoir temperatures. Decreased viscosity versus increased shear rate shows non-Newtonian behavior of the polymeric solutions. The viscosity values of the polymeric solutions are several tens of times more than the surfactant solutions viscosities even at the low concentrations. Therefore, the polymer can be considered suitable for use in the ASP-slug injection process. The viscosity of polymeric solutions decreases with increasing temperature and salinity. However, the final values are not low enough to counteract the polymer effect. Finally, an increase in oil recovery of 27.9% is achieved under the ASP slug injection process containing an anionic surfactant synthesized from waste chicken fat at CMC, NaOH alkali at 2500 ppm and the polymer extracted from Hollyhocks at 2000 ppm. At last, it should be mentioned that the main purpose of this study was to introduce a new polymer for EOR process by injecting ASP slug. However, its application does not lead to this only. Polymers are used in various oil and gas industries. Due to the properties and behavior of the polymer solution, it can be used to reduce water production from oil reservoirs, improve the properties of drilling fluids and inject it with other additives to increase oil recovery.

Comprehensive Optical Strain Sensing Through the Use of Colloidal Quantum Dots.

The adaptation of colloidal quantum dots loaded within a polymer for use in nondestructive testing can be used as an optical strain gauge due to the nanomaterial's strain sensing properties. In this paper, we utilized InP/ZnS colloidal quantum dots loaded within a polymer matrix applied onto the surface of a dog-bone foil precoated with an epoxy. By employing an empirical formula and a calibration factor, there is a propinquity between both the calculated optical strain and mechanical stress-strain reference data. Fluctuations are observed, which may be due to both additional strain responses not seen by the mechanical data and quantum dot blinking. These results and methods show the applied use of this novel optical nondestructive testing technique for a variety of structures, especially for structures that operate in harsh environments.

A estabilidade das resinas tipo bulk fill na dentística reabilitadora

Objetivo: Avaliar e contextualizar a estabilidade das Resinas Compostas do tipo bulk fill (RCBF) analisando os aspectos mecânicos, suas possíveis vantagens e desvantagens ao que se refere à resistências e contrações. Métodos: Tratou-se de uma revisão de literatura, com abordagem descritiva e caráter informativo, onde o processo de formulação se deu através de buscas por literaturas cientificas, em bases de dados, tendo como descritores: A importância da resina composta do tipo Bulk fill, sua estabilidade, utilização da polimerização e potência de irradiação. Resultados: Ao que se refere a RCBF pode ser constatado boa estabilidade, apresentando material avançado não só no aspecto estético como também em sua forma físicas e mecânicas, esse fato se deve por causa da sua matriz apresentar monômeros com propriedades avançadas dos quais diminuem de forma significativa a tensão de polimerização, tornando os monômeros mais ajustáveis permitindo assim maior ligação e adição de fotoiniciadores que sendo relacionados à canforoquinona aperfeiçoa o nível de conversão das moléculas. Considerações Finais: As RCBF são sugeridas para a restauração dos elementos dentais posteriores dos quais apontam certa estabilidade de cor, força química e mecânica, porém é necessário estudos longitudinais para analisar a estabilidade de suas propriedades a longo prazo.

Acceptor–acceptor-type conjugated polymer for use in n-type organic thin-film transistors and thermoelectric devices

The development of n -type conjugated polymers (CPs) forming an acceptor–acceptor (A–A)-type structure are quite challenging due to the synthetic limitation of imposing a functional group on the electron deficient aromatic structure. The diketopyrrolopyrroles (DPP) structure exhibits n -type characteristics; however, the extended π-structure enables stannylation at the terminal position. The stannylated DPP is beneficial for making n -type CPs, but its use in the development of n -type CPs and their application in n -type organic thin-film transistors and organic thermoelectric devices have been not extensively studied. In the present study, we synthesized the A–A-type conjugated polymer, poly [((2,5-bis(2-ethylhexyl)-3,6-di(thiophen-2-yl)-2,5-dihydropyrrolo [3,4- c ]pyrrole-1,4-dione)-5,5′-diyl)- alt -((2,7-bis(2-ethylhexyl)benzo [lmn] [3,8]phenanthroline-1,3,6,8(2 H ,7 H )-tetraone)-4,9-diyl))] (PDPP-NDI), by Stille coupling of distannylated DPP and dibrominated naphthalene diimide (NDI). The alternating copolymerization of DPP and NDI moieties led to a low-lying LUMO energy level of −4.4 eV, suitable for electron transport. The n -type organic thin-film transistors were fabricated with PDPP–NDI, and a substantial average electron mobility of 3.78 × 10 −2 cm 2 V −1 s −1 was obtained after thermal annealing. The n -type organic thermoelectric devices were developed via n -doping, and PDPP–NDI exhibited n -type thermoelectric properties, with an average power factor of 1.82 × 10 −3 μW m −1 K −2 . • An acceptor–acceptor-structured n -type alternating copolymer, PDPP–NDI, was developed. • A small bandgap of 1.03 eV and deep LUMO energy level of −4.4 eV were achieved. • The n -type characteristics of PDPP–NDI were successfully utilized in n -type OTFTs and OTE devices. • The device characteristics of both OTFT and OTE devices were fully studied and discussed.

Implant-forming polymeric 19F MRI-tracer with tunable dissolution

Magnetic resonance imaging (MRI) using 19F-based tracers has emerged as a promisingmulti-purpose noninvasive diagnostic tool and its application requires the use of various 19F-based tracers for the intended diagnostic purpose. In this study, we report a series of double-stimuli-responsive polymers for use as injectable implants, which were designed to form implants under physiological conditions, and to subsequently dissolve with different dissolution rates (t1/2 ranges from 30 to more than 250 days). Our polymers contain a high concentration of fluorine atoms, providing remarkable signal detectability, and both a hydrophilic monomer and a pH-responsive monomer that alter the biodistribution properties of the implant. The implant location and dissolution were observed using 19F MRI, which allows the anatomic extent of the implant to be monitored. The dissolution kinetics and biocompatibility of these materials were thoroughly analyzed. No sign of toxicity in vitro or in vivo or pathology in vivo was observed, even in chronic administration. The clinical applicability of our polymers was further confirmed via imaging of a rat model by employing an instrument currently used in human medicine.

Effects of long-term aging on asphalt mixes containing SBS and PP-polymer

The bulk of researches on styrene-butadiene-styrene (SBS) and polypropylene (PP) polymers for use in asphalt mixes are focused on the performance properties of these mixes without considering aging effects. SBS and PP are abounding and cheapest (on the order of 3.0–4.0 USD/kg) compared with commonly modifiers. In this research, the influence of long-term aging at 85 ± 3 °C for 120 ± 0.5 h on SBS and PP-mixes properties in terms of: stability, rigidity, resilient modulus, indirect tensile strength at 25 and 60 °C, tensile strength ratio, and rutting were determined and compared. Further pavement life and responses in terms of: fatigue strain, rutting strain, surface deflection, and percentage increase in pavement life were assessed using multi-layer elastic analysis software (BISAR). The test results of SBS-mixes showed higher resilient modulus and resistance to moisture damage, with lower stability and resistance to rutting than PP-mixes. BISAR analyses show that SBS-mixes were higher fatigue life than PP-mixes. Generally, results showed that long-term aging improves the performance of SBS and PP mixes.

Hybrid biocomposites from polypropylene, sustainable biocarbon and graphene nanoplatelets

Polypropylene (PP) is an attractive polymer for use in automotive parts due to its ease of processing, hydrophobic nature, chemical resistance and low density. The global shift towards eliminating non-renewable resource consumption has promoted research of sustainable biocarbon (BioC) filler in a PP matrix, but this material often leads to reduction in composite strength and requires additional fillers. Graphene nano-platelets (GnPs) have been the subject of considerable research as a nanofiller due to their strength, while maleic anhydride grafted polypropylene (MA-g-PP) is a commonly used compatibilizer for improvement of interfacial adhesion in composites. This study compared the thermo-mechanical properties of PP/BioC/MA-g-PP/GnP composites with varying wt.% of GnP. Morphological analysis revealed uniform dispersion of BioC, while significant agglomeration of GnPs limited their even dispersion throughout the PP matrix. In the optimal blend of 3 wt.% GnP and 17 wt.% BioC biocontent, tensile strength and modulus increased by ~19% and ~22% respectively, as compared to 20 wt.% BioC biocomposites. Thermal stability and performance enhancement occurred through incorporation of the fillers. Thus, hybridization of fillers in the compatibilized matrix presents a promising route to the enhancement of material properties, while reducing petroleum-based products through use of sustainable BioC filler in composite structures.

Stability and Behavior in Carbonate Cores for New Enhanced-Oil-Recovery Polymers at Elevated Temperatures in Hard Saline Brines

SummaryThe goal of this work was to identify viable polymers for use in the polymer flooding of high-temperature carbonate reservoirs with hard, saline brines. This study extensively examined recent enhanced-oil-recovery (EOR) polymers for stability, including new 2-acrylamido-tertbutylsulfonic acid (ATBS) polymers with a high degree of polymerization, scleroglucan, n-vinylpyrrolidone (NVP)-based polymers, and hydrophobic associative polymers. For each polymer, stability experiments were performed over a 2-year period under oxygen-free conditions (less than 1 ppb) at various temperatures up to 180°C in brines with total dissolved solids (TDS) ranging from 0.69 to 24.4%, including divalent cations from 0.034 to 2.16%. Use of the Arrhenius analysis was a novel feature of this work. This rarely used method allows a relatively rapid assessment of the long-term stability of EOR polymers. Rather than wait years or decades for results from conventional stability studies at the reservoir temperature, reliable estimates of the time-temperature stability relations were obtained within 2 years. Arrhenius analysis was used to project polymer-viscosity half-lives at the target reservoir temperature of 99°C. The analysis suggests that a set of ATBS polymers will exhibit a viscosity half-life over 5 years at 120°C and over 50 years at 99°C, representing a novel finding of this work and a major advance for extending polymer flooding to higher temperatures.For five polymers that showed potential for application at higher temperatures, corefloods were performed under anaerobic conditions. Another novel feature of this work was that anaerobic floods were performed without using chemical oxygen scavengers, chemical stabilizing packages, or chelating agents (that are feared to alter rock properties). Using carbonate cores and representative conditions, corefloods were performed to evaluate polymer retention, rheology in porous media, susceptibility to mechanical degradation, and the residual resistance factor for each of the polymers at 99°C.

Facile synthesis and coating of aqueous antifouling polymers for inhibiting pathogenic bacterial adhesion on medical devices

Bacterial colonization in the form of biofilms on surfaces causes persistent infections and is an issue of considerable concern to healthcare providers. Thus, there is an urgent need for novel modification of antibiofilm surfaces on polymeric medical devices to inhibit pathogenic bacterial adhesion. Herein, we describe the development of water-soluble, antifouling polymers (APs) containing benzene moieties capable of anchoring to hydrophobic surfaces and hydrophilic poly (ethylene) glycol and carboxyl groups to inhibit pathogenic bacterial adhesion on polymeric medical devices. We found that the optimized APs could be facilely and controllably synthesized on and modify the surfaces of commercial hydrophobic substrates in aqueous solution, with the resulting polymer-coated surfaces capable of efficiently preventing pathogenic bacterial adhesion and subsequent bacterial colonization as precursors to biofilm formation. These results suggest the potential efficacy of the developed and optimized polymers for use as an antibiofilm platform to inhibit healthcare-associated infections on various polymer-based medical devices.

Evaluation of 4-tert-Butyl-Benzhydrylamine Resin (BUBHAR) as an Alternative Solid Support for Peptide Synthesis

Following preliminary reports that introduced 4-tert-butylbenzhydrylamine resin (BUBHAR) as a novel polymer for use in solid-phase peptide chemistry (SPPS), some physical-chemical properties of its structure, certainly relevant for its application in this methodology, were compared with those of the largely used methylbenzhydrylamine resin (MBHAR). In order to rule out possible MBHAR-related commercial source effects for SPPS, we initially compared MBHAR batches acquired from three different manufacturers with homemade BUBHARs. The bead solvation properties of these two resins in solvents used in the tert-butyl (Boc-based) SPPS technique indicated that the mean swelling values of these solid supports (% volume of solvated bead occupied by the solvent) were 51% and 67% for MBHAR and BUBHAR, respectively. This result strongly suggests a good potential for the latter polymer in terms of application for application in SPPS. In order to move forward with this approach, the synthesis of the carboxy-terminal peptide fragment (Gln-Asn-Cys-Pro-(D-Arg)-Gly-amide) of the antidiuretic hormone, desmopressin ([3-Mpa∗-Tyr-Phe-Gln-Asn-Cys-Pro-(D-Arg)-Gly-amide], ∗1-[3-mercaptopropionic acid]), which our laboratory is producing routinely in large scale for the Health Secretary of Sao Paulo State. The comparative synthesis was conducted using these two resins with similar substitution degrees (~0.7 mmol/g). In contrast to MBHAR, surprisingly no need for a Gln⟶Asn recoupling reaction was observed when BUBHAR was used. This result might be due to improved solvation of the desmopressin C-terminal Asn-Cys-Pro-(D-Arg)-Gly-segment when bound to this latter resin as observed by microscopic swelling degrees of peptide-resin beads and also by greater mobility detected of peptide chains within the BUBHAR polymer backbone. This finding was determined by comparative electron paramagnetic resonance (EPR) of both peptide resins attaching the amino acid-type paramagnetic 2.2.6.6-tetramethylpiperidine-1-oxyl-4-amino-4-carboxylic acid (Toac) spin label early introduced by our group.

Preparation of Self-healing Natural Rubber/Polycaprolactone (NR/PCL) Blends

The preparation of self-healing polymers for use following mechanical failure using commercial, bio-based polymers without complex synthesis and expensive healing reagents has been very rare. In this study two commercial, bio-based polymers, natural rubber (NR) and polycaprolactone (PCL), were melt-blended to form NR/PCL blends. To increase the healing efficiency via supramolecular hydrogen bonding interactions, various amounts of acrylic acid were grafted onto the PCL. The results showed that the healing efficiency of the blends in the self-healing test at 80°Cwas higher than for blends at 60 °C due to higher molecular mobility/diffusion resulting from the molecular motions above the melting temperature of PCL which was near 55 °C in all cases. The highest healing efficiency, 62.8%, was attained for the NR/PCL-g-4AA (40/60) blend containing 4 phr PCL of AA. In addition, with the application of the shape memory-assisted self-healing (SMASH) mechanism, the healing efficiency increased further, up to 79.9%. The high shape recovery ratio (>90%) helped the crack to close faster when the sample was heated to trigger the shape memory process, leading to the increased healing efficiency in comparison with the sample without the shape memory process triggered by heating. To the best of the authors’ knowledge, there have been no similar works in the preparation of self-healing, bio-based polymer blends through the current approach so far. We suggest the synergistic effects of both the physical and chemical processes applied to commercial, bio-based polymers provide the chance of expanding the applications of these green polymers with additional functionality.

Elastomer Characterization Method for Trapped Rubber Processing.

The increasing high-volume demand for polymer matrix composites (PMCs) brings into focus the need for autoclave alternative processing. Trapped rubber processing (TRP) of PMCs is a method capable of achieving high pressures during polymer matrix composite processing by utilizing thermally induced volume change of a nearly incompressible material inside a closed cavity mold. Recent advances in rubber materials and computational technology have made this processing technique more attractive. Elastomers can be doped with nanoparticles to increase thermal conductivity and this can be further tailored for local variations in thermal conductivity for TRP. In addition, recent advances in computer processing allow for simulation of coupled thermomechanical processes for full part modeling. This study presents a method of experimentally characterizing prospective rubber materials. The experiments are designed to characterize the dynamic in situ change in temperature, the dynamic change in volume, and the resulting real-time change in surface pressure. The material characterization is specifically designed to minimize the number and difficulty of experimental tests while fully capturing the rubber behavior for the TRP scenario. The experimental characterization was developed to provide the necessary data for accurate thermomechanical material models of nearly incompressible elastomeric polymers for use in TRP virtual design and optimization.