Epoxy/POSS organic–inorganic hybrids: Viscoelastic,mechanical properties and micromorphologies

A series of epoxy resin (EP)/octa(aminpropyl)silsesquioxane (POSS‐NH₂) organic–inorganic hybrid composites (EP/POSS‐NH₂ 100/0, 95/5, 90/10, and 80/20 wt/wt) were prepared by melt casting and then curing. Viscoelastic and mechanical properties of these composites were studied by dynamic mechanical analysis and mechanical testing, respectively. Scanning electron microscopy was used to study of the micromorphologies of the composites and to elucidate the toughening mechanisms of POSS‐NH₂. POSS units incorporated into the epoxy network showed good compatibility with the resin matrix. Phase separation was not observed even at high POSS content (20 wt%). Incorporation of POSS macromer into the epoxy network after curing increased the glass transition temperature, slightly narrowed the temperature range widths of the glass transition, and lowered the intensities of their loss moduli peaks of the resultant composites. The glass transition temperature of EP/POSS‐NH₂ composites increased significantly with increasing POSS content at lower POSS content (<10 wt%), while increased slightly at higher POSS content. Both impact and flexural strengths of the hybrids reached their optimum values when 10 wt% content of POSS was introduced. POLYM. COMPOS., 28:175–179, 2007. © 2007 Society of Plastics Engineers.     

Thermal-induced simultaneous liquid-liquid phase separation and liquid-solid transition in aqueous polyurethane dispersions

Thermal-induced simultaneous phase separation and liquid-solid transition (gelation) in waterborne polyurethane dispersions has been detected morphologically and rheologically. The viscoelastic material functions, such as dynamic shear moduli, G′ and G″ complex shear viscosity, η* and loss tangent, tan δ were found to be very sensitive to the structure evolution during the gelation process and the subsequent formation of a fractal polymer gel. At the onset temperature of the gelation process, an abrupt increase in G′, G″ and η* (several orders of magnitude) was observed during the dynamic temperature ramps (2 °C/min heating-rate) over a wide range of angular frequency. The temperature dependencies of G′, G″ and tan δ were found to be frequency independent at the gel-point, T_gel, providing a fingerprint for determining T_gel of the dispersions. Furthermore, a dramatic increase in zero-shear viscosity, η₀ (v-shape) was observed at T=T_gel and found to be in good agreement with the value obtained from the tan δ versus T data. As expected, the time-temperature-superposition principle was found to be only valid for temperatures lower than the T_gel; the principle failed at T≥70 °C. The morphology of the dispersions at 70 °C for 2 h showed for 36, 38 and 40 wt% formation of a network structure having a unique periodicity and phase connectivity. A lower critical solution temperature (LCST) phase diagram was estimated based on the different morphologies of the dispersions. The coexistence of liquid-liquid and liquid-solid transitions at the same temperature range confirmed the complex behavior of the polyurethane dispersions, pointing to the need for a new theory that explicitly takes this special behavior into account.     

A study on rheological behavior of MWCNTs/epoxy composites

Rheological behaviors of multiwalled carbon nanotubes (MWCNTs)/epoxy composites with various MWCNT contents were investigated by using a time sweep and frequency sweep experiment with oscillatory rheometry. The functional groups on the acid-treated MWCNTs were investigated by fourier transfer-infrared spectroscopy (FT-IR). The composites containing acid-treated MWCNTs exhibited faster gel time than pure epoxy resins. The storage (G′) and loss (G″) moduli of the composites showed solid-like behavior owing to interaction between the MWCNTs and the epoxy resins. The 1.0 wt% MWCNT composites had the highest crosslinking activation energy (E_c) due to good dispersion and strong interfacial bonding. These results imply that three-dimensional crosslinking might take place among the hydroxyl group in epoxy resins and the carbonyl or hydroxyl group in acid-treated MWCNTs.     

Rheological behavior of aqueous mullite-albumin-methylcellulose systems

In this work, the thermogelling behavior of aqueous mullite-bovine serum albumin (BSA) suspensions was studied by dynamic rheology in order to determine the experimental conditions that must be used to form mullite green bodies by thermal consolidation. Viscoelastic properties (G′ and G′′) as a function of temperature (30–95 °C) and time were determined by temperature sweep tests and time sweep tests, respectively. On the other hand, the influence of methylcellulose (MC) (2 wt%) as a binder on the viscoelastic properties of the aqueous mullite-protein system as a function of both experimental parameters (temperature and time) was also studied. In addition, shear flow properties of aqueous mullite (40 vol%; 0.45 wt% of polyacrylic polyelectrolyte as a dispersant)–BSA (10 and 15 vol%)-MC (2 wt%) suspensions were analyzed to obtain information on the rheological behavior of the suspensions at room temperature. The results obtained showed that the presence of mullite particles and MC changed the onset temperature of gelation of the protein and increased the gelation time. Thus, both the mullite particles and methylcellulose intervened in the formation of the developed protein gel.     

Morphology and rheological behaviors of poly(ethylene terephthalate) nanocomposites containing polyhedral oligomeric silsesquioxanes

Poly(ethylene terephthalate) (PET)/polyhedral oligomeric silsesquioxane (POSS) nanocomposites were prepared by in situ polymerization. Light scattering measurement suggested that there is significant change in molecular weight arising from gel formation by chemical crosslinking during polymerization. The thermal decomposition temperatures of the composites measured at 5 wt % weight loss were 5–10°C higher than that of PET. There is no significant change in other thermal properties. Scanning electron microscopy observations suggest that there is obvious phase separation in PET/POSS composites, composites containing 1 wt % of disilanolisobutyl and trisilanolisobytyl‐POSS show fine dispersions of POSS (30–40 nm in diameter), which arise from strong interfacial interactions between POSS and PET during polymerization. The viscosity of the composites increased with the addition of POSS. The observation of a plateau region of composites containing 1 wt % of POSS in the plot of log G′ vs. log G″ indicates strong interfacial interactions between POSS and PET. Sixty‐three percent and 41% increase in tensile strength and 300 and 380% increase in modulus were achieved in the composites containing 1 wt % of disilanol‐ and trisilanol‐POSS, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Role of strain induced crystallization and oxidative crosslinking in fracture properties of rubbers

Tensile properties and crack propagation properties, especially critical strain energy release rate in mode I, G_IC, have been used to investigate fracture properties of elastomers and their relationships with microstructure. These investigations were mainly based on a series of comparisons: first, the behaviour of polychloroprene rubber (CR), undergoing stress hardening due to strain induced crystallization (SIC) and oxidative crosslinking (OCL) was compared with that of chlorinated polyethylene (CPE), which undergoes SIC but not OCL, and with a polyurethane based on hydroxyl terminated polybutadiene (PU) which undergoes OCL but not SIC. Comparisons were also made on CR between fracture behaviour at ambient temperature, where SIC occurs and at 100 °C where there is no SIC. Finally, oxidative crosslinking was used to vary in a continuous way the crosslink density in CR and PU, in order to evaluate the role of crosslinking in fracture behaviour.     

Network chain density and relaxation of in situ synthesized polyacrylamide/hectorite clay nanocomposite hydrogels with ultrahigh tensibility

Nanocomposite hydrogels (NC gel) D-AM and S-AM were synthesized through in situ polymerization of acrylamide (AM) with hectorite clays of Laponite RD and RDS, respectively. The tensile performance of the NC gel was observed at different crosshead speeds and all of the NC gels exhibited an extremely high tensibility, e.g., the elongation at break even higher than 4000%, except for two samples with the lowest Laponite content of 1 w/v%. Strong tensile hysteresis was observed in the elongation-reversion curve, indicating a slow relaxation in the NC gels. Dynamic moduli G′ and G″ within linear viscoelasticity illustrated that the network structure was formed in these gels with the junction of Laponite platelets. The Laponite RD showed stronger gelation capability than the tetrasodium pyrophosphate modified Laponite RDS. The relaxation modulus G(t) for the NC gels was found to be similar to the slow rubber relaxation with the critical exponent n of about 0.16, much lower than 0.66-0.71 for the critical gel at the sol-gel transition. In comparison, the chemically cross-linked hydrogel showed almost no relaxation during the same time interval. The effective network chain density of the NC gel was determined from equilibrium shear modulus, which was evidently lower than that of the chemically cross-linked hydrogels. The present results reveal that the high deformability of these NC gels comes from their low effective network chain density with moderate relaxation.     

Nanotailoring of polyurethane adhesive by polyhedral oligomeric silsesquioxane (POSS)

The development and commercialization of nanoparticles such as nanoclays (NCs), carbon nanotubes (CNTs) and polyhedral oligomeric silsesquioxanes (POSS) offers new possibilities to tailor adhesives at the nanoscale. Four types of POSS, with reactive mono-functional groups of isocyanatopropyl, glycidoxypropyl, aminoethyl and non-reactive octaphenyl, were incorporated in concentrations of 1, 3 and 5 wt% into a polyurethane (PU)-based adhesive. Thermo-mechanical bulk properties were studied using dynamic mechanical analysis (DMA). Adhesive properties were characterized in shear and peel modes. Atomic force microscopy (AFM) was used to study the nanoscale morphology. DMA measurements indicated that the neat PU possessed a glass transition temperature (T _g) of ≈ 30°C. The T _g of PU/POSS-glycidoxypropyl nanocomposite adhesive increased gradually with POSS concentration to 50°C for 5 wt%. PU/POSS-octaphenyl nanocomposite adhesive exhibited an increased T _g by 10°C for 5 wt%. The incorporation of POSS-isocyanatopropyl in the PU had no effect on the T _g. With respect to shear properties of POSS-octaphenyl-, POSS-isocyanatopropyl- and POSS-glycidoxypropyl-based PU nanocomposite adhesives, shear strength improved by 230, 178 and 137%, respectively, compared to neat PU. POSS-aminoethyl exhibited lower shear and peel strengths, while POSS-isocyanatopropyl provided the best balance of both higher shear and peel strengths compared to neat PU. It was concluded that the grafted functional group on the POSS and its reactivity with the PU network components were the decisive factors with respect to the thermo-mechanical, morphological and adhesive properties of the resulting nanocomposite adhesives. Consequently, the POSS/polyurethane based nanocomposite adhesives could be tailored for a large range of applications.     

Synthesis,Morphology and Viscoelastic Properties of Epoxy/Polyhedral Oligomeric Silsesquioxane (POSS) and Epoxy/Cyanate Ester/POSS Nanocomposites

TriSilanolPhenyl-polyhedral oligomeric silsesquioxane (POSS-1) (C₄₂H₃₈O₁₂Si₇), 1–15 wt%, was incorporated into aliphatic epoxy resin (Clearstrem Products, Inc.) with aliphatic diamine curing agents and cured. This epoxy resin was also blended with an equal weight (50/50 w/w) of aromatic cyanate ester resin, Lonza’s PT-15, and 1–15 wt% of POSS-1 and cured. These composites were characterized by FT-IR, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (X-EDS), dynamic mechanical thermal analysis (DMTA) and three-point bending flexural tests. XRD and X-EDS measurements were consistant with partial molecular dispersion of the POSS units in the continuous matrix phase, together with POSS aggregates. TEM and SEM show that POSS-1-enriched nanoparticles are present in the matrix resins of both the epoxy/POSS and epoxy/cyanate ester/POSS-1 composites. The storage bending moduli, E′, in the rubbery region and the glass transition temperatures, T_g, of epoxy and epoxy/cyanate ester 1-5% POSS-1 composites are higher than those of the reference resins. Small amounts (≤5 wt%) of POSS-1 improved E′ and T_g of both systems and raised flexural strengths and moduli.     

Preparation and rheological studies on the solvent based acrylic pressure sensitive adhesives with different crosslinking density

On the basis of synthesis of a series of solvent based acrylic pressure sensitive adhesives (PSAs) with different crosslinking density, the thermal and rheological properties were characterized. T_g values were increased after crosslinked with MDI, and the thermal stability was also improved. Rheological studies were performed via frequency sweep, amplitude sweep, temperature sweep patterns, respectively. The creep recovery properties were also researched. In this way, it was proved that the linear viscoelastic (LVE) range was elongated as the feeding MDI increased, the elastic modulus (G′) of the acrylic PSAs was obviously increased after crosslinked with MDI whereas hardly making any change to the viscous modulus (G″). In the frequency sweep pattern, the PSAs samples behave as pseudoplastic non-Newtonian fluid; and zero shear viscosity increased as the feeding MDI mass ratio was increased, after discussing the cross-over frequency (?^?) and the relaxation time t_R, it can be concluded that the addition of MDI would make for the improvement of the elasticity of the PSAs; in the temperature sweep pattern, it could be seen that the cross-over temperatures (where G″=G′) were 34 and 70 °C for the samples crosslinked with 0 wt% and 0.1 wt% MDI, respectively. When the mass ratio of MDI fed was higher than 0.1 wt%, even though the temperature increased to 120 °C, the samples remained elastic (G′>G″). In the creep recovery test, it was noteworthy that as the feeding ratio of MDI was increased, the creep recovery properties of the acrylic PSAs were substantially improved. And for the same sample, as the applied constant stress increased from 200 to 1000 Pa, the recoverable proportion of the materials was principally not changed in that all the experiments were carried out within the linear viscoelastic range of the samples. And the sample crosslinked with 0.5 wt% MDI shows the highest 180° peel stress.     

Effect of SiC interphase on the mechanical,high-temperature dielectric and high-temperature microwave absorption properties of the SiCf/SiC/Mu composites

In this study, SiC interphase was prepared via a precursor infiltration-pyrolysis process, and effects of dipping concentrations on the mechanical, high-temperature dielectric and microwave absorption properties of the SiC_f/SiC/Mu composites had been investigated. Results indicated that different dipping concentrations influenced ultimate interfacial morphology. The SiC interphase prepared with 5 wt% PCS/xylene solution was smooth and homogeneous, and no bridging between the fiber monofilament could be observed. At the same time, SiC interphase prepared with 5 wt% PCS/xylene solution had significantly improved mechanical properties of the composite. In particular, the flexural strength of the composite prepared with 5 wt% PCS/xylene solution reached 281 MPa. Both ε′ and ε′′ of the SiC_f/SiC/Mu composites were enhanced after preparing SiC interphase at room temperature. The SiC_f/SiC/Mu composite prepared with 5 wt% PCS/xylene solution showed the maximum dielectric loss value of 0.38 at 10 GHz. Under the dual action of polarization mechanism and conductance loss, both ε′ and ε′′ of the SiC_f/SiC/Mu composites enhanced as the temperature increased. At 700 °C, the corresponding bandwidth (RL ≤ ?5 dB) of SiC_f/SiC/Mu composites prepared with 5 wt% PCS/xylene solution can reach 3.3 GHz at 2.6 mm. The SiC_f/SiC/Mu composite with SiC interphase prepared with 5 wt% PCS/xylene solution is expected to be an excellent structural-functional material.     

Interface structure of poly(ethylene terephthalate)/silica nanocomposites

The interface structure of the poly(ethylene terephthalate) (PET)/silica nanocomposites was characterized by Fourier transform infrared and solid-state nuclear magnetic resonance. Our study reveals that PET chains are grafted onto the surface of silica nanoparticles, and they form branched and lightly crosslinking structures during the polycondensation. Gel permeation chromatography measurements indicate that the grafted PET chains have a lower molecular weight and broader distribution. Furthermore, a model has been developed to elucidate the interaction of an entanglement network between silica and PET chains that lead to enhancements of G′, G″ and η* values of PET/2 wt% silica nanocomposites.     

Investigation of pre-reaction and cure temperature on multiscale dispersion in POSS–epoxy nanocomposites

Dispersion of monoamine-functionalized polyhedral oligomeric silsesquioxane (POSS) in an epoxy network was improved by pre-reacting the POSS with excess epoxide and employing a high-temperature cure. DGEBA/DDS networks were formulated with 2.5 and 10 wt% POSS. In some samples, POSS was pre-reacted with DGEBA. The hybrid materials were characterized via SEM, TEM, and DMA. The microscopy and DMA results evinced a multiscale morphology with POSS-rich glassy domains, nano- and microcrystallites, and crystallite agglomerations. For a loading level of 2.5 wt% POSS, the sample with unmodified POSS cured at 125 °C had inorganic crystallites on the order of 1–5 μm and agglomerations on the order of 10–20 μm, whereas the sample with pre-reacted POSS cured at 180 °C had near-perfect dispersion with no agglomerations and very few POSS crystallites. The 10 wt% POSS epoxies also showed improved dispersion with pre-reaction and increasing cure temperature. The dispersion improvements were attributed to the enhanced miscibility of the pre-reacted POSS and the increased rate of POSS reaction into the growing epoxy network at a higher cure temperature.     

Phenolic resin-trisilanolphenyl polyhedral oligomeric silsesquioxane (POSS) hybrid nanocomposites: Structure and properties

The structure and properties of organic-inorganic hybrid nanocomposites prepared from a resole phenolic resin and a POSS mixture containing >95 wt% trisilanolphenyl POSS was investigated by POM (polarized optical microscopy), SEM, TEM, WAXD, FT-IR, DSC, and TGA techniques. Composites with 1.0-10.4 wt% of POSS were prepared by dissolving the POSS and the phenolic resin into THF, followed by solvent removal and curing. Both nano- and micro-sized POSS filler aggregates and particles were shown to be heterogeneously dispersed in the cured matrix by POM, TEM, SEM, and X-EDS. POSS was found everywhere, including in both dispersed phase domains and in the matrix. The nanocomposite morphology appears to form by a multi-step POSS aggregation during the process of phase separation. Both the matrix and dispersed ‘particulate’ phase domains are mixtures of phenolic resin and POSS. POSS micro-crystals act as the core of the dispersed phase. The bigger dispersed domains consist of smaller particles or aggregates of POSS molecules that exhibit some order but regions of matrix resin are interspersed. A WAXD peak at 2θ∼7.3° indicates crystalline order in the POSS aggregates. This characteristic peak's intensity increases with an increase in POSS loading, suggesting that more POSS molecules have aggregated or crystallized. FT-IR spectra confirm that hydrogen bonding exists between the phenolic resin and POSS Si-OH groups. This increases their mutual compatibility, but H-bonding does not prevent POSS aggregation and phase separation during curing. TGA measurements in air confirmed the temperature for 5% mass loss in increases with increase of POSS loading and at T>550° the thermal stability increases more sharply with POSS loading. The nanocomposite glass transition temperatures (T_g) are only slightly be affected by the POSS filler.     

Elongational behavior of epoxy during curing

Elongational behavior of epoxy (epoxy/curing agent = 100/0.5, w/w) cured at various conditions over the critical gelation time was investigated. Dynamic viscoelastic measurements of the epoxy system were performed and the critical gelation time of epoxy was determined according to the frequency dependence of G′ and G″ proposed by Winter and Chambon. Elongational behavior of epoxy cured for various times were measured. Epoxy, cured over the critical gelation time, showed strain hardening and elongational behavior similar to a crosslinked rubber. Increase of elongational viscosity of the sample occurred early, and the sample broke at small strain as curing time increased. The effect of strain rate on the elongational stress of epoxy cured near the critical gelation time was measured at various strain rates. For epoxy cured for critical gelation time only, high stress at a small strain rate was represented as strain rate increased. When increasing curing time further, the tensile stress converged on a single curve regardless of strain rate, and samples broke at nearly the same stress and strain. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Evaluation of a redox-initiated in situ hydrogel as vitreous substitute

Currently there is no material clinically available as a long-term vitreous substitute. In this study, an in-situ gelation system based on α-poly(ethylene glycol) methacrylate (α-PEG-MA) and a redox-initiated radical polymerization/crosslinking reaction was evaluated for this purpose. Ammonium persulfate (APS) and N,N,N′,N′-tetramethyl ethylene diamine (TMEDA) were used as initiators. The gelation time, rheological properties, reaction kinetics and swelling profiles were studied in detail and the system with 10 wt% of α-PEG-MA and 8 mM APS/TMEDA was chosen as the optimal material for in vivo studies. Using the rabbit as the animal model, we showed that the system did form a space-filling and transparent gel in the vitreous cavity, and the inflammation response could be controlled to an acceptable level.     

Critical phenomenon during photoinitiated gelation at different temperatures: A Photo-DSC study

The behaviour of photoinitiated radical polymerization of an 80 wt% epoxy diacrylate (EA) and 20 wt% tripropyleneglycoldiacrylate (TPGDA) mixture with 2-mercaptothioxanthone (TX-SH) photoinitiator was studied at different temperatures by using photo-differential scanning calorimetric (Photo-DSC) technique. All photopolymerization reactions were carried out under the same conditions. It was observed that all conversion curves during gelation at different temperatures present nice sigmoidal behaviour which suggests the application of the percolation model. Observations around the critical time, called the glass transition point (t_g), taken to reach the maximum rate of polymerization (Rp_max) show that the gel fraction exponent (β) obeyed the percolation model. The produced β values were found to be around 0.50, predicting that the system under consideration belongs to the same universality class. However, Rp_max and the final conversion (C_s) values were found to increase when the temperature was increased up to a certain value. On the other hand, t_g values decreased and became saturated as the temperature was increased.     

Novel water and oil repellent POSS-based organic/inorganic nanomaterial: Preparation, characterization and application to cotton fabrics

A series of polyhedral oligomeric silsesquioxane (POSS) based hybrid terpolymers P(POSS-MMA-(HFPO)₃MA) were synthesized and characterized by NMR, FT-IR, GPC, DSC and TG. The thermal properties of these terpolymers were improved by the introduction of POSS cage. The cotton fabrics coated with these terpolymers possessed excellent water and oil repellency. The water and salad oil contact angle could be achieved from ∼140° to 152° and from ∼127° to 144° respectively as the content of POSS in the terpolymer increased from 6.4 wt% to 13.4 wt%. Compared with P(MMA-(HFPO)₃MA) copolymer-coated cotton fabrics, POSS-based terpolymer coated cotton fabrics showed better oil repellency with a tendency of first increasing and then decreasing with an increase of the POSS content. The n-hexadecane (surface tension: 27.4 mN/m, 20 °C) contact angle reached ∼117° for coated cotton fabrics with terpolymer containing 9.5 wt% of POSS.     

Gelation studies on acrylic acid‐based hydrogels via in situ photo‐crosslinking and rheology

The gelation characteristics of acrylic acid (AA)‐based hydrogels were investigated using real time in situ photocrosslinking and rheological measurements. The gel point and gelation times were established using Winter–Chambon criteria. Frequency independence of tan δ was observed in all cases, such that G′ and G″ scaled as ～ωⁿ. The Flory–Stockmayer theory was used alongside other indices in order to probe the gelation and the post‐gelation characteristics of the critical gels and the fully formed hydrogels. Network relaxation exponents (n) were influenced by the concentrations of AA and methylene bis‐acrylamide. The gel stiffness (S) decreased with an increase in the concentration of the monomer and of the concentration of the crosslinker, while network branching decreased (lower fractal dimensions) at the gel point. The conversion at the gel point was found to be iso‐conversion with respect to the intensity of the UV irradiance used in the photocrosslinking reactions (1–20 mW/cm²). Thus, network clusters and the crosslinking reaction mechanism were the same irrespective of radiation intensity, although the rates of the reactions were affected. Having sufficient amounts of reactive species at the time of cure drive the crosslinking reactions beyond the gel point to greater crosslink density and smaller mesh sizes. The effects of auto‐acceleration and free‐volume were observed and shown to have key effects on the gelation mechanisms and the branching topographies of the network, when the concentration of the known polyacrylamide medium were not controlled. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46691.     

Improvement in volume resistivity and morphology of a blend of polyolefin elastomer with linear low-density polyethylene

A silane moisture-cured polyolefin elastomer/linear low-density polyethylene (LLDPE) blend was prepared through a two-step silane-grafting method (Sioplas Process) in an industrial scale twin-screw extruder. The silane-grafted compound was used to make wire and cable coatings. In this work, the effect of some interactive parameters on quality of the products prepared by the above method has been studied, while so far, there have been less experimental investigations. The volume resistivity of cross-linked compound was changed from 2.96 × 10¹⁴ to 7.41 × 10¹⁴ Ω cm with increasing LLDPE component by maximum 10 wt%. Surface morphology of the product was corrected with reduction in benzoyl peroxide (BPO) concentration from 0.2 wt% to 0.13 wt%. BPO at this level acted as an initiator in grafting reaction of vinyl trimethoxysilane. The curing condition and specimen preparation method by injection molding and/or extrusion were factors which influenced the hot-set test results at 200 °C. The results of tensile and elongation studies showed a maximum value of 9 MPa and 397% for the tests, after 6 h curing. With increases in curing time at a specified temperature, the gel content of the cross-linked compound was increased and reached its maximum value. The maximum gel content values were found to be approximately 60%, 80%, and 82% at temperatures of 25, 60, and 85 °C, respectively. The hardness, density, and tear strength of the samples did not vary significantly with the curing temperature.