Types Of Rubber Research Articles

Comparative life cycle assessment of three types of crumb rubber modified asphalt under different system boundaries

This study employs a life cycle assessment (LCA) to quantify the environmental impacts of three crumb rubber recycling technologies in asphalt rubber (AR) mixtures: wet, dry, and terminal blend. The analysis identifies key factors affecting their environmental performance across the life cycle. Results were characterized into climate change, stratospheric ozone depletion, fine particulate matter, terrestrial acidification, marine eutrophication, freshwater ecotoxicity, human toxicity, and Land use. Dynamic rankings of the three AR technologies along their life cycle stages in each impact category would enable identification of the influencing factors and provide reference for the further improvement. This study reveals that dry technology is likely to have the most significant environmental impacts across all categories (51.85 %-100 %), whereas terminal blended technology generally presents the lowest impact (51.85 %-88.89 %), with the exception of freshwater ecotoxicity (33.33 %) and human toxicity (22.22 %), where wet technology shows the least impact. The analysis underscores the importance of asphalt mixture designs, with appropriate binder content, potential reduction in surface course thickness, and reduced maintenance frequency, as strategies to enhance the environmental performance of AR technologies. The study concludes that the environmental performance of AR pavement is highly dependent on their in-service durability, with scenario-based analysis indicating that adequate durability ensures environmental effectiveness.

TREATMENT FOR REMOVING ZN COMPOUNDS FROM SILICA-FILLED VULCANIZED RUBBER AND ANALYSIS OF SILICA AGGREGATE DISPERSION

ABSTRACT Treatment of silica-filled rubber vulcanizates with a diethyl ether/concentrated hydrochloric acid solution for 96 h at room temperature can remove most Zn compounds smaller than approximately 90 nm, which account for most of the residual ZnO, rubber-soluble Zn compounds and ZnS resulting from crosslinking reactions of by-products. However, a very small number of giant ZnO particles of a few micrometers in size remain after such treatment. In the silica-filled SBR matrix treated for 96 h, a significant increase in crosslink density and Young’s modulus was observed due to crosslinking reactions after HCl was removed from HCl-added rubber molecules. This increase in crosslink density was accompanied by an increase in the surrounding layer of bound rubber closest to the silica of the two bound rubber layers around it and a decrease in the rubber matrix of the same volume. It is inferred that there was little change in the aggregate structure of the silica due to these volume changes. Alternatively, ultra-small X-ray scattering measurements of the treated samples showed shoulders derived from silica aggregates and clear high-resolution X-ray computed microtomography (X-ray CT) images were obtained due to the removal of Zn compounds smaller than approximately 90 nm in size. The relationship between these shoulders and the size of silica aggregates obtained by X-ray CT imaging was qualitatively consistent, and it was not affected by the presence or absence of bis-(3-triethoxysilylpropyl) tetrasulfide and 1,3-diphenylguanidine, but was dependent on the rubber type. The distance between nearest neighbor particles of silica aggregates, determined by X-ray CT imaging, also depended on the types of rubber.

Research on rubber classification and recognition based on terahertz time-domain spectroscopy and improved honey badger algorithm

The identification of different rubber materials is crucial to ensuring the quality of rubber products. In order to quickly and effectively identify the types of rubber, reduce the impact of counterfeit rubber on the market. This study proposes a rubber identification method based on terahertz time-domain spectroscopy (THz-TDS), Chemometry, and Improved Honey Badger Algorithm (IHBA). Initially, the absorption spectra of eight types of rubber within the 0.2–1.6 THz range are obtained and calculated using THz-TDS. This is followed by data preprocessing using Savitzky-Golay and Principal component analysis(PCA). The optimization effects of genetic algorithm (GA), grid optimization algorithm (GRID), particle swarm optimization algorithm (PSO) and honey badger algorithm (HBA) on support vector machine (SVM) model parameters were compared respectively. The HBA-SVM model achieves 96.88 % recognition accuracy on the prediction set, which is higher than other models and shows excellent parameter optimization ability.To further improve accuracy, Bernoulli chaotic mapping, cosine density factor, and Cauchy mutation are introduced for improvement. Compared with the original model, the IHBA-SVM model improves the accuracy of rubber recognition from 96.88 % to 98.96 %. Furthermore, compared with other models, the IHBA-SVM model achieved the highest classification accuracy. In summary, this study provides technical support and reference for the rapid identification of rubber, which is of great significance for ensuring the quality of rubber products.

Penyuluhan Dan Safari Keluarga Berencana Dalam Meningkatakan Penggunaan KB Implan Dan Iud Di Klinik Pratama Elvi Diana Kecamatan Medan Johor, Kota Medan Tahun 2024

Background: Uncontrolled population growth will have many negative impacts. The central government and regional governments have made efforts to reduce the large population growth rate. The government's efforts include socializing two children through the Family Planning program. Intrauterine Device (IUD) is a contraceptive device that is good for women. This tool is very effective and does not need to be remembered every day like birth control pills and birth control injections every month or every three months. For mothers who breastfeed, the IUD does not affect breast milk, the flow or level of breast milk (ASI). Meanwhile, an implant is a type of contraception in the form of an implant made from a type of silastic rubber containing hormones, installed in the upper arm. The implant can be used for a long term of 5 years and is reversible. The advantages of contraception are high effectiveness, implant failure rate, 1 per 100 women per year in the first 5 years, low user failure, once installed there is no need to remember anything. The implant contains levonorgestrel which is a progesterone hormone (Hasliana, 2020). The aim of this community service program (PKM) is to increase the use of implant contraception and IUD contraception at the Pratama Elvi Diana Clinic in 2024. The method used is that counseling on targets is carried out orally. The results are based on the results of the service implementation. Participants in this activity were PUS who visited the Pratama Elvi Diana Clinic totaling 42 people.

Fatigue Life Prediction of a Rubber Mount Considering the Self-Heating by the Hysteresis Loss of the Rubber Material Subjected to Cyclic Loadings

Failure analysis and fatigue life prediction are important steps in the design procedure of industrial products to assure the safety and reliability of their components. A model to calculate the heat generation by the hysteresis loss in natural rubber subjected to cyclic loads in a uniaxial direction was introduced and the fatigue life prediction model of the rubber was established based on the theory of continuum damage mechanics (CDM). Dynamic mechanical analysis (DMA) was used to measure the viscoelasticity of the rubber material. The heat generation in the rubber material was calculated using a subroutine with the programming software C++ and the temperature rise in the rubber material was analyzed by a thermal finite element analysis (FEA) method. Then static mechanical FEA models of a rubber mount were established and the strain contours of the rubber mounts at various loads were calculated. The total principal strain was used as the fatigue parameter to predict the fatigue life of the rubber mount. Finally, the fatigue lives of the rubber mounts at various loads were measured on a test rig to validate the accuracy of the prediction method. The test results indicated that the fatigue lives predicted considering the temperature rise agreed better with the test results compared with those not considering the temperature rise and we suggest our fatigue prediction method should be applicable to both rubber and other types of components.

Unlocking the potential of lignin: Towards a sustainable solution for tire rubber compound reinforcement

This study tackles the persistent challenge of producing highly reinforced lignin-rubber composites, emphasizing the transformation of agro-industrial residues into value-added products. To address this challenge, we introduce a novel approach termed “in-situ surface modification utilizing a thermo-chemo-mechanical approach” which incorporates the utilization of biomass-derived kraft lignin and a thermally stable organofunctional surface modifier, specifically (3-aminopropyl) triethoxysilane. The resulting material exhibits unprecedented tensile strength (∼15 MPa) along with ∼300 % elongation at break, while typical gum rubber offers 1–2 MPa tensile strength. Additionally, for the other tensile properties like 100 %, and 200 % tensile modulus, the improvement is 7-fold (∼5.6 MPa) and 10-fold (∼11.3 MPa), respectively. Furthermore, this composite presents a higher degree of reinforcement than a passenger car radial (PCR) tire model compound (tensile strength ∼14.5 MPa, 100 % tensile modulus ∼2.2 MPa, and 200 % tensile modulus ∼5.6 MPa) comprised of silica and polysulfide-based coupling agent, with exactly a similar loading of filler. The dynamic mechanical and stress relaxation behavior of the composites are critically discussed concerning the dispersion of the lignin in the sSBR/BR rubber matrix. The morphological orientation and involved chemical interaction in the presence of a surface modifier are also studied in detail. Tear fatigue analysis using pure shear specimens indicates superior fracture toughness at a lower tearing energy regime compared to silica-filled PCR tire compounds. Overall, this study showcases the potential of lignin-reinforced elastomers, offering a promising route for sustainable engineering materials and commercial viability.

Comparison of degradation effects for three types of crumb rubber used on a sport surface

Comparison of degradation effects for three types of crumb rubber used on a sport surface

Review of Recent Progress on Silicone Rubber Composites for Multifunctional Sensor Systems.

The latest progress (the year 2021-2024) on multifunctional sensors based on silicone rubber is reported. These multifunctional sensors are useful for real-time monitoring through relative resistance, relative current change, and relative capacitance types. The present review contains a brief overview and literature survey on the sensors and their multifunctionalities. This contains an introduction to the different functionalities of these sensors. Following the introduction, the survey on the types of filler or rubber and their fabrication are briefly described. The coming section deals with the fabrication methodology of these composites where the sensors are integrated. The special focus on mechanical and electro-mechanical properties is discussed. Electro-mechanical properties with a special focus on response time, linearity, and gauge factor are reported. The next section of this review reports the filler dispersion and its role in influencing the properties and applications of these sensors. Finally, various types of sensors are briefly reported. These sensors are useful for monitoring human body motions, breathing activity, environment or breathing humidity, organic gas sensing, and, finally, smart textiles. Ultimately, the study summarizes the key takeaway from this review article. These conclusions are focused on the merits and demerits of the sensors and are followed by their future prospects.

A comparative study of the mechanical and thermal properties of EPDM rubber/cement kiln dust composite cured by ionizing radiation

In this work, cement kiln dust (CKD) will be studied as an unconventional filler for ethylene-propylene-diene terpolymer (EPDM) rubber as an alternative to silica, which is widely used as filler for many types of rubber. (EPDM)/CKD rubber composites were fabricated using ionizing radiation. EPDM rubber was blended with different portions of cement-kiln dust 5, 10, 15, 20, 25, and 30 phr (phr = parts per hundred rubber). The prepared composites were cured by exposing to different doses of gamma rays up to 150 kGy to enhance the crosslinking of the EPDM rubber. The thermo-mechanical properties of the EPDM/CKD and EPDM/Si composites were investigated as a function of irradiation dose. The results showed a significant improvement in elongation and tensile strength by incorporating cement dust into EPDM rubber up to 20 phr, which is not significantly different from composites incorporated with silica. Gamma irradiation significantly improved the properties of all formulations.

The Effect of Different Accelerators on the Vulcanization of EPDM Rubber

: EPDM (ethylene propylene diene monomer) is a type of synthetic rubber. The products of rubber have great importance in every part of life. EPDM rubber has high tensile strength, high tension, toughness, and is weather resistant. Therefore, EPDM (ethylene-propylene-diene rubber) is widely used in many fields. The aim of this study is to examine the effect of accelerator type on mechanical properties and vulcanization characteristics of EPDM rubber. We used the accelerators; thiazole, sulfonamides, dithiocarbamate, thiuram, and guanidine groups. The results show that the fastest cure time and the best tensile strength are achieved with dithiocarbamates for EPDM rubber.

Effectiveness of Starch Nanocrystals on Mechanical and Shape Memory Behaviour of Smart Rubber

Shape memory rubber (SMR) is a type of smart rubber that can undergo reversible changes when exposed to external stimuli such as temperature, solvent, pH, light, magnetic field and oxidation. Lightly crosslinked rubber demonstrated shape memory behaviour without any initial heat treatment. However, the strength of lightly crosslinked natural rubber latex (NRL) film cured by sulphur is relatively low. With the concept of sustainability in mind, the idea of fabricating green smart material for continuous development has motivated researchers to explore the realms of sustainable materials. This research aims to investigate the mechanical behaviour of starch nanocrystals (SNC) reinforced rubber composite films. To this end, the emphasis is laid on evaluating the effectiveness of SNC on shape memory effect (SME) of rubber nanocomposite films. In the current work, up to 8 wt% of SNC synthesized by acid hydrolysis was incorporated into NRL and the mixture was cast to form rubber nanocomposite films. SNC effectively increased the modulus and energy-storing potential of the rubber nanocomposite films. Moreover, the shape memory behaviour of the rubber nanocomposite films improved significantly with SNC content, leading to increased shape fixity (Sf) and full shape recovery (Sr).

Sulfur and Peroxide Vulcanization of the Blends Based on Styrene-Butadiene Rubber, Ethylene-Propylene-Diene Monomer Rubber and Their Combinations.

Rubber blends based on styrene-butadiene rubber, ethylene-propylene-diene monomer rubber and a combination of both rubbers were cured with different sulfur and peroxide curing systems. In sulfur curing systems, two type of accelerators, namely tetramethylthiuram disulfide, N-cyclohexyl-2-benzothiazole sulfenamide, and combinations of both accelerators were used. In peroxide curing systems, dicumyl peroxide, and a combination of dicumyl peroxide with zinc diacrylate or zinc dimethacrylate, respectively, were applied. The work was aimed at investigating the effect of curing systems composition as well as the type of rubber or rubber combinations on the curing process, cross-link density and physical-mechanical properties of vulcanizates. The dynamic mechanical properties of the selected vulcanizates were examined too. The results revealed a correlation between the cross-link density and physical-mechanical properties. Similarly, there was a certain correlation between the cross-linking degree and glass transition temperature. The tensile strength of vulcanizates based on rubber combinations was higher when compared to that based on pure rubbers, which points out the fact that in rubber combinations, not only are the features of both elastomers combined, but improvement in the tensile characteristics can also be achieved. When compared to vulcanizates cured with dicumyl peroxide, materials cured with a sulfur system exhibited higher tensile strength. With the application of co-agents in peroxide vulcanization, the tensile strength overcame the tensile behavior of sulfur-cured vulcanizates.

Environmentally Friendly Natural Coagulants in the Coagulation Process in the Rubber Industry

This research evaluates the use of natural coagulants, such as soursop and Aegle marmelos (Maja), in the latex coagulation process of the GT 1 clone type, compared with chemical coagulants such as formic acid and acetic acid, to gain an understanding of the characteristics of the rubber produced. Three types of crumb rubber (SIR 3 CV, SIR 3L, and SIR 3 WF) are produced from latex, while SIR 5, SIR 10, and SIR 20 are produced from treated latex coagulum. Rubber quality criteria are explained in the Indonesian Rubber Standard (SIR 3L/3WF) SNI 06-1903-2011. The use of natural coagulants, especially soursop, and Maja, in the coagulation of GT 1 clone latex shows an influence on coagulation time, Dry Rubber Content (DRC), initial plasticity (Po), Plasticity Retention Index (PRI), ash content, dirt content, and substance content evaporate. The results showed that natural coagulants had slower coagulation times, higher DRC values ​​(especially in maja), and better PRI values ​​compared to chemical coagulants. Despite having higher ash content, dirt content, and volatile matter content, all types of coagulants meet rubber quality standards. This research provides in-depth insight into the potential and advantages of natural coagulants, especially soursop, and maja, in the environmentally friendly rubber industry. In addition, analysis of rubber characteristics, such as plasticity, resistance to heating, and content of certain components, provides a comprehensive understanding of the impact of the use of natural coagulants on rubber quality.

The effect of 1,3-(bis citraconimidomethyl)Benzene on the reversion of cured ethylene-propylene-diene monomer (EPDM) rubber using semi-efficient vulcanisation (SEV) system and a nano zinc oxide as an activator

This study presents a comprehensive analysis of the impact of the anti-reversion agent, 3-(bis citraconimidomethyl) Benzene, Perkalink 900, on the properties, with a focus on reversion tendencies, of carbon black-filled ethylene-propylene-diene monomer (EPDM) rubber compounds cured using a semi-efficient vulcanization (SEV) sulfur curing system with various accelerators. The research highlights that the presence of Perkalink 900 significantly prolongs the optimum cure times for all rubber compounds, reducing ∆torques, especially in fast-curing systems. Crosslink density (CLD) exhibits minimal sensitivity to Perkalink 900, which effectively prevents reversion, even reaching zero in certain compounds. Reversion extent varies with the chosen curing system, and the concentration of Perkalink 900 plays a key role in its control. Perkalink 900 enhances Shore A hardness, indicating a denser and stiffer rubber, while tear strength and elongation at break improve. Tensile strength remains stable or slightly increases, and the modulus response varies based on the curing agent and Perkalink 900 loading. ATR-FTIR spectra confirm Perkalink 900 presence, with peak intensities correlating with its concentration. Additionally, a new Alder-ene reaction mechanism between EPDM and Perkalink 900 is proposed. Overall, the study establishes Perkalink 900 as an effective anti-reversion agent, proving its potential to significantly enhance rubber compound properties. Future investigations could focus on optimizing Perkalink 900 concentrations for specific applications and exploring its interactions with diverse rubber types and curing systems.

Phase behavior of rubber and supercritical CO2: Operating parameters and swelling characteristics

AbstractThis study aims to compare the difference in the swelling process between styrene butadiene rubber (SBR) and natural rubber (NR) in ScCO2. A high‐pressure visual stainless‐steel autoclave was used to carry out swelling measurements based on the sample dimensions. The swelling rates for both rubbers followed a first‐order kinetic model. The diffusion coefficient for CO2 was determined from the change in the swelling degree with time. The shrinking process for the expanded rubber obeyed a second‐order kinetic model. A 2‐level full factorial experimental design was employed to discuss the influence of variables on rubber swelling and CO2 diffusion. Temperature and pressure were found to have a great influence on the equilibrium swelling degree, swelling rate and diffusion coefficient. For both SBR and NR, the maximum equilibrium swelling degrees were observed at 120°C and 20 MPa, yielding values of 1.18 and 1.16, respectively. The maximum diffusion coefficient reached approximately 3 × 10−9 m2 s−1 for both types of rubber at 120°C and 8 MPa. The crosslink density failed to affect these three responses, but the volume of expansion and the shrinkage rate were found to significantly decrease and increase, respectively, with increasing crosslink density. The motion of polymer segments forced by ScCO2 led to rearrangement of the material structure, which governed the nature of swelling, expansion, and shrinkage. Due to a lower number of entanglements and a weak electrostatic interaction exists between CO2 and the π‐system, SBR can absorb more CO2 and easily restructure than NR under the same conditions, resulting in higher equilibrium swelling degree, larger expansion and faster shrinkage than NR.Highlights Swelling of nature rubber and styrene‐butadiene rubber in ScCO2 is compared. Swelling degree is positively correlated with temperature and pressure. Diffusion coefficient increases with temperature but decreases with pressure. Swelling degree varies with rubber type, while CO2 diffusion dose not. Crosslink density significantly affects expansion and shrinkage of rubber.

Determination of the limits of operational loads of rubber shock absorbers during compression

Determining the limits of operational loads of rubber shock absorbers is an urgent task in the development of methods of non-destructive control of their condition. Therefore, the object of research is the influence of the limit values of the parameters of rubber shock absorbers during their static compression under harsh operating conditions. One of the most problematic issues is cylindrical shock absorbers with a form factor of less than 1.0. In the work, rubber shock absorbers of different hardness were used, which are model samples for tests of cylindrical shock absorbers with a form factor of 0.42, which were carried out on a laboratory stand. The study of compression process of rubber shock absorbers is an urgent task in modelling the conditions of their operation. The obtained results make it possible to simulate the most effective diagnostic parameter of rubber shock absorbers during compression and to establish its limit and permissible values. It has been established that different rubber hardnesses provide different compression rates, which can be used to study non-destructive testing of shock absorbers, especially under which conditions they can be used in practice. According to the indicators of relative deformation during compression, the use of rubber shock absorbers from the group of high hardness is recommended for more severe load conditions during exploitation. Soft and medium-hard rubbers are characterized by an increased relative deformation of the shock absorber's geometric size (height) during compression, which can lead to their destruction under increased loads. The obtained results on model samples can be checked on rubber shock absorbers manufactured in industrial conditions. The conducted research allows to create methods of choosing rubber shock absorbers for certain operating conditions depending on the coefficient of its shape. Limits of indicators simulating operating loads for different types of rubber shock absorbers have been established, which can be used when choosing a type of rubber for certain load conditions, and choosing a reinforcing material for the rubber array of the shock absorber and its shape.

Research on classification methods for rubber based on terahertz time-domain spectroscopy with data fusion strategy

Rubber, an essential industrial product, plays a crucial role in industry and human life. However, some manufacturers of rubber use inferior, recycled or low-cost rubber materials to replace high-quality rubber products. Therefore, in order to ensure industrial production, protect natural environment and ensure personal safety, it is of great economic and social significance to enable rapid and non-destructive qualitative identification of rubber products. In this paper, eight different types of black rubber, including Nitrile Butadiene Rubber (NBR), Choloroprene Rubber (CR) and Ethylen Propylen Diene Monomer (EPDM), were selected as research objects. Terahertz Time-Domain Spectroscopy (THz-TDS) technology was utilized to get the absorption spectra, refractive index spectra and time-domain spectra of these samples for exploring the differences between different types of rubber in terahertz spectra. To reduce the data volume, three band selection algorithms were employed to extract features from the absorption spectra and refractive index spectra, and temporal features of time-domain spectra were extracted for subsequent data processing. In the selection of classification model algorithms, K-Nearest Neighbor (KNN), Random Forest (RF) and Supervised Kohonen Neural Networks (S-Kohonen) were employed to recognize these spectral data. To fully exploit the latent information within these data and considering the possibility of the loss of partial information in single-type signal, a feature-level data fusion method was applied to different optical parameter signals to obtain more information about terahertz spectra during the process of data modeling. The results of the research indicated that the model with the highest prediction accuracy was the KNN model, with an accuracy of 97.37%, when refractive index spectra and time-domain spectra were fused as inputs, the F1-score reached 99.64. The performance of data fusion was noticeably better than that of a single-type signal. This study validates the feasibility of using terahertz time-domain spectroscopy for qualitative identification of different types of rubber.

Characteristics of Sand-Waste Tyre Rubber Composite as Backfill Material

Waste tyre rubber offers an alternative to natural sand as a backfill material, potentially reducing the dependency on natural sand usage in construction. The purpose of this study is to investigate the properties of waste rubber as a potential backfill material for retaining walls and to assess the shear strength characteristics of the sand-rubber composite when used as a backfill for retaining walls, ultimately identifying the optimal sand-rubber composite ratio for effective backfill application. This study employed sieve analysis and specific gravity testing to identify the physical attributes of waste tyre rubber. Subsequently, direct shear box tests were conducted utilizing ratios of 100%, 50%, 75%, and 25%. Two types of rubber were utilized in this study Granulated Rubber (GR) with particle sizes ranging from 1 to 5 mm, and Mulch (MR) with particle sizes exceeding 25 mm. The findings reveal that the Cu value for waste rubber is less than 2.50 and the Gs value is less than 1.5, indicating favourable characteristics. Moreover, the 25% GR and MR compositions exhibit the highest shear stress values at 0.0347 N/m² and 0.0296 N/m², respectively. In conclusion, it has been determined that the optimal proportion of waste rubber for the application of the sand-waste tyre rubber composite as a backfill material is 25%.

Experimental investigation on mechanical properties of sustainable roller compacted concrete pavement (RCCP) containing waste rubbers as alternative aggregates

Different types of solid waste are generated every year due to global industrialization. With the rapid growth of the automobile industry, the disposal of billions of waste rubbers (WR), which pollute the environment and cannot be disposed of properly, is emerging as an urgent matter of concern. Recycling waste rubbers by using them on pavements will contribute to the elimination of ecological and economic problems. In this study, the effects of waste rubbers on the mechanical properties of roller-compacted concrete pavement (RCCP) were investigated by obtaining sustainable RCCP mixtures using different types of waste rubbers as coarse and fine aggregate substitutes. In this context, waste rubbers with three different sizes (powder, crumb and shredded) were substituted for aggregate by volume at seven levels (0%, 2.5%, 5%, 7.5%, 10%, 20% and 30%) with a maximum of 30% in RCC mixtures. Unit weight, mechanical properties, modulus of elasticity and ultrasonic pulse velocity (UPV) were evaluated and compared according to the waste rubber content in the RCC mixtures. In addition, microstructural analysis of the mixtures was performed through scanning electron microscopy (SEM). The experimental results revealed that the compressive, flexural and splitting tensile strength and modulus of elasticity decreased with increasing waste rubber content in RCC. The utilization of waste rubber increased the ductility of RCC and decreased the density to produce lighter concrete. RCC with a compressive strength of about 30 MPa could be obtained by substituting 10% of waste rubber for aggregate. Thus, the utilization of high waste rubber content in pavements was feasible. This study can contribute to a more sustainable RCCP production by replacing natural aggregates with waste rubbers.

The mechanism of the influence of radiation heat flux on the combustion behavior of raw rubbers

Understanding the combustion behavior of rubbers is crucial for predicting their fire hazards. The cone calorimeter experimental results in this study confirm that the combustion behavior of raw rubbers depends on the rubber type and the heat flux. Natural rubber and ethylene-propylene-diene monomer rubber exhibit heat release rate (HRR) curves with only one peak at the end of the burning stage under all tested heat fluxes. At higher heat fluxes, the HRR curves of polybutadiene rubber (BR) and styrene butadiene rubber (SBR) exhibit a single peak; at heat fluxes lower than 20 kWm−2, two HRR peaks were observed. The proposed mechanism model with the crosslink reaction as the key factor can explain the emergence of two-peak HRR curve and has been proved through experiments and simulations. For BR and SBR at 15 kWm−2, the specimens exhibit two upper layers at ignition time. The surface pyrolysis layer seems to be covered by black film or char, with the crosslink degree as high as 84.23–100 %. The second crosslink reaction layer exhibits a higher decomposition temperature Td,5 % than the original rubber. Based on reaction kinetics and thermodynamics data derived from TG/DSC experiments, the novel pyrolysis model taking crosslink reaction and thermal decomposition of crosslinked intermediate into account well predicts the HRR curves obtained at varied heat fluxes. The conversion of raw rubber to the crosslinked intermediate plays an important role in the reduction of HRR immediately after ignition, resulting in the first HRR peak.