Curing Characteristics Research Articles

Reconstructed three-dimensional structure of gas-foamed polycaprolactone/cellulose nanofibrous scaffold for biomedical applications

One of the unavoidable issues with the bio-scaffolding process is the collapse of the visually appealing external three-dimensional (3D) sponge-like structure and the internal porous and multilayered morphology of a gas-foamed nanofibrous scaffold. Herein, a gas-foamed polycaprolactone/cellulose (g-PCL/CL) nanofibers scaffold is first prepared by electrospinning PCL/cellulose acetate, followed by deacetylation and then Sodium borohydride-assisted gas-foaming technique. The deformed 3D architecture of g-PCL/CL nanofiber is finally reconstructed by mixing it with chitosan (CS) solution and molding. This straightforward method leverages the mechanical strength of PCL, the hydrophilic properties of CL, and the curing characteristics of chitosan. The physical characterization validated the successful reformation of the 3D architecture of the CS + PCL/CL scaffold demonstrating the unique porous interior structure assembled with nanofiber-reinforced pore walls. This molding process with chitosan solution enables the formation of mechanically enhanced 3D scaffolds with improved structural integrity, as evidenced by the increased compressive strength of the CS + PCL/CL scaffold (~95 kPa). In vitro studies further demonstrate improved cell adhesion, differentiation, and proliferation for the CS + PCL/CL scaffold. These findings suggest that the structurally reconstructed CS + PCL/CL composite scaffold possesses suitable characteristics to act as a potential bioscaffold, paving the way for promising strategies to retain the structural integrity of collapse scaffolds.

Construction of epoxy composites with double alternating “rigid-flexible” structures: Curing kinetics and thermal/mechanical properties

The curing rate, post-curing modulus, and strength of epoxy resin are key performance indicators for epoxy resin-based composites. Optimizing these factors is essential for improving production processes and expanding practical applications. Functionalized rigid-flexible bilayer transition interfaces between nano-ZnO and epoxy resins were developed using chitosan (CS) and 1,2,3-Tris(glycidyloxy)propane (GTE). Their impact on the curing characteristics, rheology, and mechanical properties of the composites was investigated. The activation energies of pure EP and systems containing ZnO, ZnO-CS, and ZnO-CS-GTE were studied using non-isothermal calorimetry, obtaining 53.604 KJ/mol, 52.548 KJ/mol, 56.66 KJ/mol, and 51.482 KJ/mol, respectively. ZnO-CS-GTE showed a notably stronger promotional effect. Nano-ZnO inhibited gelation due to filler aggregation at 80 °C for 4 min, while ZnO-CS-GTE promoted gelation in just 2.6 min owing to its functional groups, achieving a modulus near 1 GPa after curing. Mechanical studies revealed that the tensile, flexural, and compressive strengths of the ZnO-CS-GTE system increased by 48.52 %, 32.67 %, and 45.01 %, respectively, with flexural and compressive moduli rising by 15.14 % and 15.76 %. The rigid-flexible interface enhanced the dispersion of epoxy resin and strengthened interfacial adhesion.

Preparation of UV curable acrylamide modified epoxy resin and performance in 3D printing

A novel UV-curable 3D printing resin was synthesized by combining diglycidyl ether of bisphenol A (DGEBA) and acrylamide (AAM) to create a UV-curable acrylamide-modified epoxy resin prepolymer. This prepolymer was then uniformly mixed with the photoinitiator TPO and the reactive diluent hydroxyethyl methacrylate (HEMA). By adjusting the prepolymer content, UV-curable 3D printing resins were formulated with prepolymer concentrations of 30 wt%, 40 wt%, and 50 wt%, respectively. Infrared spectroscopy and nuclear magnetic resonance studies indicated that the amino groups in acrylamide reacted with the epoxy groups. When the prepolymer was added at concentrations of 30 wt% and 40 wt%, the viscosity met the requirements for UV-curable 3D printing. Upon completion of curing, these three distinct resins exhibited high mechanical strength, with tensile strength reaching up to 59.42 MPa and flexural strength peaking at 72.25 MPa. The elongation at break ranged from 2.60 % to 4.91 %. Scanning electron microscopy was used to examine the UV-cured 3D printed samples, and comparison with the design files revealed that the printed samples exhibited excellent dimensional stability. The study results indicated that this novel UV-curable epoxy vinyl resin formulation possessed excellent mechanical properties, suitable curing characteristics, and high resolution, making it a highly promising prepolymer for UV-curable 3D printing.

Influence of different composite curing agents on the rapid curing characteristics and mechanical performance of epoxy resins

To address the need for rapid in situ plugging and repair of hydraulic machinery and chemical pipelines and to resolve the issue that a single curing agent cannot simultaneously achieve rapid curing and excellent mechanical properties in epoxy resin systems, this study explores the use of composite curing agents. In particular, effective formulations are designed for mixing fast and slow curing agents, studying their effects on the curing behavior, curing quality, and mechanical properties of epoxy resins and elucidating their influence mechanisms. The results indicate that three resin systems meet the requirements for rapid curing (curing time within 30 min): 4A6B/EP, 2A8B/EP, and 0A10B/EP. Among them, 4A6B/EP exhibits the best curing quality and mechanical properties. In particular, 4A6B/EP demonstrates the lowest values of curing shrinkage rate, internal curing stress, average pore size, porosity, and cumulative pore volume. Its low internal stress and low defects reduce the stress concentration, while more efficient deflection and branching of internal cracks enhance its deformation resistance. Consequently, 4A6B/EP shows the highest microhardness, fracture toughness, tensile strength, Young’s modulus, and elongation after fracture. Based on the comprehensive evaluation of rapid curing characteristics and mechanical properties, the 4A6B/EP system offers the best overall performance. Therefore, it is recommended as the preferred resin system for rapid plugging and repair of composite materials, providing a theoretical basis and technical support for boosting the application of epoxy resin composite materials in high-tech fields.

Adjusting the surface quality of printed components via controlling dispersant content to improve the electrical performance of DLP-printed PZT ceramics and devices

This paper aims to enhance the surface quality of digital light processing (DLP) printed lead zirconate titanate (PZT) components by controlling the content of BYK-111 dispersant, thereby improving the electrical properties of the resulting printed piezoelectric ceramics and devices. 55 vol% high solid loading PZT slurries with different dispersant contents were prepared and assessed for their dispersion stability, rheological behavior and curing characteristics. The slurry containing 1 wt% BYK-111 demonstrated ideal rheological properties, notably achieving a low viscosity of 1.37 Pa·s at 100 s−1. The surface roughness of the printed ceramic component was reduced to 69.3 nm, representing a 57.1 % improvement in surface quality compared to other dispersant levels. The printed PZT ceramic exhibited superior piezoelectric performance, with a piezoelectric constant d33 reaching 445 pC/N, surpassing most existing 3D-printed macro-sized piezoelectric ceramics. Furthermore, a DLP-printed 1–3 piezoelectric array was encapsulated to fabricate an acoustic emission (AE) sensor, which achieved a low substrate noise level of 31 dB and a high signal-to-noise ratio of 62 dB, outperforming commercial sensors. The optimal BYK-111 content not only ensures favorable dispersion stability and rheological properties in the slurry, but also significantly enhances the surface quality and density of the printed ceramic components, ultimately leading to the production of high-performance piezoelectric ceramics and devices.

The effect of silane‐modified carbon black and nano‐silica, individually and in combination, on the performance of ethylene–propylene–diene monomer rubber

AbstractThis study assesses the effectiveness of a specially developed surface‐modified carbon black, both on its own and in combination with nano‐silica, as a hybrid filler for ethylene–propylene–diene monomer (EPDM) rubber compounds. The modification process, which included treatment with a silane coupling agent, resulted in enhanced curing characteristics. The ∆Torque values for compounds incorporating the modified carbon black exceeded those of other formulations by 25.85%. Scanning electron microscopy (SEM) analysis demonstrated improved filler dispersion and better compatibility between rubber and filler due to the surface modification. The silane‐modified carbon black showed considerable enhancements in mechanical properties, particularly in tear resistance, with increases in tensile and tear strength of 22.46% and 34.86%, respectively, following surface treatment. Dynamic mechanical analysis (DMA) indicated the influence of both surface modification and filler type, revealing that the combination of modified carbon black and nano‐silica achieved a reduction in rolling resistance of 20.41% and enhanced ice and wet grip performance by 7.95%. Additionally, modified carbon black displayed varying effects on the glass transition temperature. Thermal gravimetric analysis (TGA) confirmed that the thermal stability of the compounds was consistent, while solvent resistance improved with surface modification, as shown by swelling ratios. Thermodynamic analysis indicated that the surface modification of carbon black positively influences the elasticity and chain mobility of the rubber compounds studied. In conclusion, the careful selection and optimization of filler materials and their modifications are essential for customizing the properties of rubber compounds to satisfy specific performance criteria and applications.Highlights Promising EPDM compounds were prepared with Silane‐Modified CB and Nano‐Silica. Silane‐modified CB effectively improved the curing properties of the EPDM compound. The ΔTorque and cross‐link density of modified CB/EPDM show the highest value. Modified CB/Nano‐Silica/EPDM exhibited significant improvement in tear strength. Modified CB/Nano‐silica/EPDM have lower rolling resistance and higher wet grip.

Influence of Tire Reclaimed Rubber (TRR) Loadings on Cure Characteristics and Mechanical Properties of Natural Rubber/Styrene Butadiene Rubber (NR/SBR) Blends

This investigation delves into the potential utilization of Tire Reclaimed Rubber (TRR) as a filler within Natural Rubber/Styrene Butadiene Rubber (NR/SBR) blends. TRR is obtained from discarded rubber tires and stands as a pertinent resource that necessitates its effective utilization in the production of eco-friendly, value-added rubber-based products. This is due to the rising of rubber waste tires which causes environmental concerns and all sorts of pollution. The TRR filled NR/SBR blends were fabricated using two-roll mills. The loadings of TRR were varied ranging from 20 phr to 100 phr. The aim of this study is to investigate the influence of TRR loading on the curecharacteristics and mechanical properties of blends in terms of tensile strength, rebound resilience, hardness, and density. It is found that the MH and Δ torque exhibited a decreasing trend which would indicate a reduction in crosslink density due to high loading of TRR. Meanwhile, the ts2 and tc95 increased with the increase of TRR loading. Furthermore, the tensile strength, hardness, density, and rebound resilience of blends experience a steady reduction with the incorporation of TRR. The decrement of those properties might be due to the low molecular weight of TRR. Regarding the collective findings, TRR emerges as a potentially viable candidate for waste rubber repurposing, serving as a non-reinforcing filler with optimal utility achieved at a 30 phr loading level.

Comparison of Plasmid Curing Efficiency across Five Lactic Acid Bacterial Species.

With the recent stringent criteria for antibiotic susceptibility in probiotics, the presence of antibiotic resistance genes and plasmids associated with their transfer has become a limiting factor in the approval of probiotics. The need to remove genes related to antibiotic resistance and virulence through plasmid curing for the authorization of probiotics is increasing. In this study, we investigated the curing efficiency of ethidium bromide, acridine orange, and novobiocin at different concentrations and durations in five strains of plasmid-bearing lactic acid bacteria and examined the curing characteristics in each strain. Limosibacillus reuteri and Lacticaseibacillus paracasei exhibited curing efficiencies ranging from 5% to 44% following treatment with ethidium bromide (10-50 μg/ml) for 24-72 h, while Lactobacillus gasseri showed the highest efficiency at 14% following treatment with 10 μg/ml novobiocin for 24 h. Lactiplantibacillus plantarum, which harbors two or more plasmids, demonstrated curing efficiencies ranging from 1% to 8% after an additional 72-h treatment of partially cured strains with 10 μg/ml novobiocin. Plasmid curing in strains with larger plasmids exhibited lower efficiencies and required longer durations. In strains harboring two or more plasmids, a relatively low curing efficiency with a single treatment and a high frequency of false positives, wherein recovery occurred after curing, were observed. Although certain strains exhibited altered susceptibilities to specific antibiotics after curing, these outcomes could not be attributed to the loss of antibiotic resistance genes. Furthermore, the genomic data from the cured strains revealed minimal changes throughout the genome that did not lead to gene mutations.

Hydroxyapatite-Filled Acrylonitrile-Butadiene Rubber Composites with Improved Cure Characteristics and Reduced Flammability.

The goal of this work was to develop acrylonitrile-butadiene (NBR) elastomer composites filled with hydroxyapatite (HAP) characterized by improved cure characteristics and resistance to burning. Silane, i.e., (3-aminopropyl)-triethoxysilane, ionic liquid, i.e., 1-decyl-3-methylimidazolium bromide and surfactant, i.e., cetyltrimethylammonium bromide, were used to improve the filler's dispersibility in the elastomer matrix and to reduce the time and temperature of vulcanization. The effects of HAP and dispersants on the cure characteristics, crosslink density and physico-chemical properties of NBR composites were explored. The additives used, especially the ionic liquid and surfactant, effectively improved the dispersion of HAP in the NBR matrix. The amount of HAP and the dispersant used strongly affected the cure characteristics and crosslink density of NBR. The optimal vulcanization time significantly increased with HAP content and was pronouncedly reduced when ionic liquid and surfactant were applied. In addition, ionic liquid and surfactant significantly lowered the onset vulcanization temperature and improved the crosslink density and hardness of the vulcanizates while impairing their elasticity. HAP and dispersants did not significantly affect the damping properties or chemical resistance of NBR vulcanizates. Above all, application of HAP considerably enhanced the resistance of vulcanizates to thermo-oxidative aging and reduced their flammability compared with the unfilled NBR.

Synergistic effect of a new binary accelerator system on curing characteristics and properties of styrene–butadiene rubber vulcanizates

Synergistic effect of a new binary accelerator system on curing characteristics and properties of styrene–butadiene rubber vulcanizates

Effect of immediate curing at elevated temperatures on the tensile and interfacial properties of carbon fiber-epoxy composites

Elevated temperature conditions known to improve curing from the onset and during the process of immediate curing are not available in the field, which can hinder the mechanical performance of these strengthening systems. In this study, mechanical testing and material characterization were conducted to identify the effects of subjecting nanomodified epoxy and fiber-reinforced nanomodified epoxy composites to room temperature (RT) (30 °C) and elevated temperature (110 °C) from the onset of curing. Static tensile testing and interfacial adhesion tests were conducted to evaluate the mechanical performance. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were performed to determine curing characteristics to inform on the immediate curing of nanomodified resins cured under the two temperature conditions. Scanning electron microscopy was performed to identify Carbon nanotube (CNT) dispersion characteristics. Overall, due to the incorporation of CNTs in epoxy, RT curing results in upto 62% increase in strain at failure. By supplying additional energy during immediate curing with elevated temperatures, a 51% increase in strength and 42% increase in Youngs Modulus can be observed in the nanomodified epoxy. In CFRP-epoxy composites, due to the incorporation of CNTs in the epoxy, RT curing results in upto 27% increase in strain at failure. By supplying additional energy during immediate curing with elevated temperatures, upto 133% increase in strain at failure is observed and upto 17% increase in strength is observed. CNTs incorporated in CFRP-epoxy composites demonstrated upto 50% increase in interfacial adhesion whereas supplying additional energy for their immediate curing with elevated temperatures, upto 130% increase in interfacial adhesion was observed. TGA and DSC results supported the mechanical observations and show a need for immediate curing when CNTs are used in epoxy matrices.

Resistivity and Piezoelectrical Behavior of the Smart Oil Well Cement Incorporated with Aluminum Oxide and Iron Oxide Nanoparticles—Experimental and Analytical Study

Abstract The effects of individually adding 1 % nano aluminum oxide (NA) and 1 % nano iron oxide (NF) on the curing, compressive piezoelectric, and stress-strain characteristics of cement (Class H) were studied and quantified. X-ray diffraction and thermogravimetric analysis were used to evaluate the cement (class H) with and without the 1 % NF and 1 % NA modification. The cement’s initial electrical resistivity (ER) incorporated with 0.1 % conductive filler was improved by 16 and 31 %, respectively, with 1 % NF and 1 % NA. Including 1 % NF and 1 % NA enhanced the stress at the failure of the cement paste by 26 and 39 % and 17 and 42 %, respectively, after curing times of 1 and 28 d. The nonlinear Vipulanandan p-q curing model was employed to anticipate ER change with curing age. Depending on the curing period and type of nanomaterial, the piezoelectrical (piezoresistivity) of “smart” cement containing NF and NA was more significant than normal cement by 500 times. The nonlinear curing model has been applied to model variations in ER with the curing period. The gauge factor model relating strain to resistivity changes under compressive stress was also developed using a relation model.

Coffee grounds as sustainable filler for bio‐based rubber composites

AbstractUsing biological/renewable resources as filler or modifier in both thermoplastics and rubbers has been of a great interest in order to reduce negative effects of traditional petroleum/natural gas based fillers. In this study, the main goal was the use of spent (waste) coffee grounds as a natural alternative filler to carbon black in acrylonitrile butadiene rubber (NBR) based compounds. Carbon black (CB) was partially replaced with fresh as well as spent coffee grounds (SCG) in NBR compound formulation. Stabilization effect of fresh coffee grounds was also investigated. Cure characteristics, physico‐mechanical, thermal, morphological, and dielectric properties of the bio‐based composites were tested and compared with the control (reference) compounds. Processability has been affected positively in the case of using coffee grounds thanks to the presence of triacyl groups in coffee. Up to 20% higher elongation at break values were measured when coffee is partially replaced with CB. Abrasion loss and oil resistance could be retained for coffee containing compounds. In conclusion, SCG were found to be a good natural alternative filler for bio‐based NBR composites without a significant change in material properties.Highlights Spent coffee grounds ‐ a sustainable filler in bio‐based NBR composites Both fresh and spent coffee grounds are successful stabilizers Physico‐mechanical, thermal, and dielectric properties are comparable

Effects of adding n-amyl alcohol, dimethylfuran to fuel on soot formation in aviation kerosene diffusion flame

As the main energy consumption of aviation and aerospace, the study of combustion characteristics of aviation kerosene is of great significance. In this paper, through the self-built experimental system, the combustion flame characteristics of pure aviation kerosene, aviation kerosene mixed with n-amyl alcohol, aviation kerosene mixed with dimethylfuran were studied under different working conditions, and the physicochemical properties of soot particles generated in the flame, and the effects of mixing n-amyl alcohol and dimethylfuran on the formation of soot particles were analyzed from the microscopic perspective. The results show that: 1. The soot particles in the combustion of aviation kerosene mixed with n-amyl alcohol and dimethylfuran show some characteristics of amorphous structure, unclear outline and incomplete curing; 2. Under K-D20 condition, nitrates are included in particulate matter generated by soot; 3. After mixing n-amyl alcohol and dimethylfuran, the degree of graphitization continues to decrease.

Study on the curing characteristics and properties of phthalonitrile resin cured with organic guanidine

Bisphenol A-based phthalonitrile resin was synthesized by nucleophilic substitution reaction from bisphenol A and 4-nitrophthalonitrile, and then the obtained resin was cured with sulfaguanidine as a novel curing agent. The curing characteristics, kinetics, thermal stability and dynamic mechanical property were studied by standard thermal analysis techniques including DSC, TGA, and DMA. The peak temperature of exothermic peak ( Tp) and apparent activation energy ( Ea) of sulfaguanidine cured phthalonitrile resin were 263.20°C and 76.6 kJ·mol−1 respectively, much lower than those of traditional aromatic diamine cured resin. Moreover, the resin cured by sulfaguanidine showed excellent thermomechanical properties and thermal stability. The glass transition temperature ( Tg) was 284.8°C, the initial thermal decomposition temperature ( Td,5%) was 439.6°C, and the char yield at 800°C was 62.1% in nitrogen atmosphere. To sum up, organic guanidine cured phthalonitrile resin exhibits excellent curing characteristics (low Tp and Ea) and high thermal properties, which provides a promising approach to preparing phthalonitrile resin with high comprehensive performance.

Vat photopolymerization based Photoinhibition aided Ceramic additive manufacturing (PinCAM)

Vat photopolymerization (VPP) in ceramic additive manufacturing (CAM) faces challenges due to high viscosity from ceramic powder loading, necessitating interruptive recoating steps. Ceramic particles also attenuate and divert irradiated light, causing reduced cure depth and over-curing, leading to slow print, weak interlay adhesion, and dimensional errors. This study introduces photo inhibition-aided CAM (PinCAM) using dual-wavelength digital light processing to mitigate these issues. PinCAM employs two optical masks for initiation and inhibition at different wavelengths. While previous research focused on polymers, this work evaluates inhibition's effects in suspension-based VPP-CAM. Modeling and experiments examine inhibition and curing characteristics, print speed, dimensional accuracy, surface roughness, and microstructure. Preliminary results suggest that photoinhibition has the potential to enhance geometrical and surface properties as well as particle distribution homogeneity of green ceramic components without significantly compromising print speed. Understanding inhibition's impact will aid further research in PinCAM optimization for rapid and precise ceramic manufacturing.

Effect of Titanium Dioxide on Cure Characteristics and Physico Mechanical Properties of High-Temperature Vulcanizing Silicone Rubber Composites

Silicone rubber (SiR), a vital elastomer, is extensively used in producing various engineering and general products, owing to its distinctive properties. Despite the remarkable properties, SiR-based products require anti-microbial agents such as titanium dioxide, TiO2 to negate black mold issues. Still, adding this agent alters the composites' processability and physical and mechanical properties. This study examined the impact of adding different TiO2 content as fillers on silicone rubber composites' processability, physical properties, and mechanical properties. Raw materials of 20-hardness high-temperature-vulcanization (HTV) SiR- reinforced with various TiO2 contents at 0.0, 0.3, 0.6 and 1.2 wt% were prepared using a two-roll mill. The results indicated SiR composites reinforced with 0.3 wt% TiO2 exhibited the best performance with a tensile strength of 1.49 MPa, elongation at break of 340.87%, modulus 100% of 0.664 MPa, modulus 300% of 0.822 MPa, and modulus 500% of 0.954 MPa. This performance can be attributed to the efficient crosslink density and the effective interactions between the TiO2 and silicone rubber particles at this concentration. Structural and morphological analyses further corroborated the results. Consequently, it can be inferred that silicone rubber reinforced with 0.3 wt% titanium dioxide holds the potential for formulating silicone rubber compounds that necessitate anti-microbial properties.

Cure characteristics and mechanical properties of natural rubber vulcanizates filled with untreated pyrolytic tire char

AbstractUntreated pyrolytic tire char was used in natural rubber (STR20) composites as single filler at loadings of 30–70 phr and co‐filler with carbon black (N330) at a total loading of 50 phr. The results were compared with rubbers filled with N330 and crumb rubber at 30 phr. The effects of fillers on cure characteristic, crosslink density, filler dispersion in natural rubber vulcanizates and their mechanical properties were investigated. The slight reversions were seen for the cure characteristics of 70 phr‐char‐filled and all co‐filler samples because the sulfur amount in the char together with the added sulfur could shift the vulcanization system from EV to SEV, whereas plateau cure curves were seen for the rest. While the highest tensile strength of char‐filled sample was obtained at 50 phr loading, whose tensile strength was about 88% of the N330 sample at 30 phr, 70‐phr‐char filled sample was superior in surface hardness, abrasion resistance and tear strength to N330 sample at 30 phr. For rubber with co‐fillers, the mechanical properties depended on the mass ratio of N330 to pyrolytic tire char. Therefore, it is possible to use untreated char as reinforcing filler for suitable applications according to their properties.

Curing characteristics and performance of a bio-based polyurethane engineered sealant with high bonding strength: Effect of R value and chain extender content

Polyurethane (PU) engineering sealants can be used to fill construction joints and pavement cracks with excellent practical results. However, traditional engineering sealants have the disadvantages of poor strength and raw materials that are not environmentally friendly. In this paper, a novel composition system of bio-based polyurethane engineering sealant was developed. The effects of the isocyanate/macroglycol molar ratio (nNCO/nOH, R value) for component A and the contents of amine chain extender (AME) on the curing characteristics and properties of the PU sealant were investigated using a series of experiments. Firstly, the curing process of the sealant was studied by Fourier transform infrared spectroscopy (FTIR) test, surface drying time test and gel time experiments. Secondly, the basic physical properties of the sealant were studied by tensile and hardness tests. And the water resistance of the sealant was judged. Then, the characteristics of molecular movement of polyurethane sealant were analyzed by dynamic mechanical analysis (DMA). The tensile cross-sections of the specimens were observed by scanning electron microscopy (SEM). Finally, the thermal stability of sealants was studied by thermogravimetric (TG) analysis. The results indicated that the material developed in this research can be used as a high-performance engineering sealant in actual projects. The increase in the R value and the decrease in AME content resulted in a longer curing process of the sealant. The rise of R value and AME content was able to raise the tensile strength, bonding strength and hardness of the sealant. The water resistance of the sealant was better. Also, the glass transition temperature (Tg) and storage modulus could also be increased and the thermal stability of the previous stage could be reduced by increasing the R value and AME content. Considering both the performance and construction requirements, the optimum R value and AME contents are recommended to be 2.1 and 1.4%, respectively.

Simultaneous optimization of the vulcanization characteristics and mechanical properties of chloroprene and natural rubber blend by response surface methodology

Chloroprene rubber (CR) is an expensive and frequently used material in many industries. Thus, a blend of natural rubber (NR) and CR can be used to balance cost and product performance. In this research, the primary objective is to achieve the ideal blend of CR/NR rubber for automotive industry by simultaneously optimizing various response variables, including hardness, tensile strength (TS), vulcanization index (CRI), torque difference and Tan δ. This optimization process is carried out using response surface methodology (RSM) and desirability functions. The study delves into examining the influence of accelerators, retarders, curatives, and the ratio of NR in the final batch on both curing characteristics and mechanical properties. The investigation is conducted through the application of analysis of variance (ANOVA) and linear/nonlinear regression models with the assistance of Design Expert 11. When the quantities of the fillers, TMTM80, DP80, S80, and CTPI80, are at their optimum levels of 1.08, 1.78, 3.5, and 0.96 PHR, respectively, and the NR ratio in the final masterbatch is around 27%, the estimated values for Tan δ, hardness, and TS are approximately 0.144, 55.183 Shore A, and 21.085 MPa, respectively. The observations from the validation experiments align with the predicted outcomes, as all response variables fall within the 95% prediction interval. It is noteworthy to mention that prior research has not attempted simultaneous optimization for CR/NR blend, incorporating these fillers.