Ambient temperature cross-linkable acrylic latexes: effect of cross-link density, glass transition temperature and application temperature difference on mechanical properties

The influence of both beam irradiation and step cross-linking on high abrasion furnace (HAF) carbon black loaded natural rubber (NR) vulcanizates are reported. With irradiation, a higher cross-link density, ν, thermal conductivity, λ, and glass transition temperature, Tg, have been observed for such materials, as compared with the un-irradiated ones. There is also a decreased specific heat capacity, Cp. Meanwhile, the step cross-linking process has a slight effect on the cross-link density, glass transition temperature and thermal properties of these composites. The results of such changes in thermal conductivity are explained with the help of a simple modified model.

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Experimental Cold-Cured Nanostructured Epoxy-Based Hybrid Formulations: Properties and Durability Performance

Polymers ◽

10.3390/polym12020476 ◽

2020 ◽

Vol 12 (2) ◽

pp. 476 ◽

Cited By ~ 2

Author(s):

Mariaenrica Frigione ◽

Mariateresa Lettieri ◽

Francesca Lionetto ◽

Leno Mascia

Keyword(s):

Mechanical Properties ◽

Glass Transition ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Thermogravimetric Analysis ◽

Low Temperature ◽

Thermal Degradation ◽

Ambient Temperature ◽

Durability Performance ◽

Different Levels

Different hybrid epoxy formulations were produced and cold-cured, monitoring the properties development during low temperature curing and aging. All systems were based on silane functionalized bis-phenol A (DGEBA) resins (Part A), cured at ambient temperature with two amine hardeners (Part B). The different components of the formulations were selected on their potential capability to bring about enhancements in the glass transition temperature. The durability of the produced hybrids was probed in comparison to the corresponding neat epoxies by monitoring changes in glass transition temperature (Tg) and flexural mechanical properties after exposure to different levels of humidity and immersion in water and at temperatures slightly higher than the local ambient temperature, in order to simulate the conditions encountered during summer seasons in very humid environments. The thermal degradation resistance of the hybrid systems was also evaluated by thermogravimetric analysis.

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Boron nitride for modification of rubber based on isoprene elastomer

Voprosy Materialovedeniya ◽

10.22349/1994-6716-2019-100-4-105-112 ◽

2020 ◽

pp. 105-112

Author(s):

K. S. Zhansakova ◽

E. N. Eremin ◽

G. S. Russkikh ◽

O. V. Kropotin

Keyword(s):

Mechanical Properties ◽

Boron Nitride ◽

Gradual Increase ◽

Physical And Mechanical Properties ◽

Curing Time ◽

Cross Link ◽

Start Time ◽

Link Density ◽

Cross Link Density ◽

Isoprene Rubber

The work studies vulcanization characteristics of elastomers based on isoprene rubber filled with carbon black N330 and boron nitride (BN). The influence of the boron nitride (BN) concentration on technological, dynamic, physical and mechanical properties of elastomers has been researched. The application of boron nitride for producing rubber with good properties has been considered. With a gradual increase of the inert filler BN concentration up to 35%, a decrease in the curing rate by 33% and polymer cross-link density by 26% is observed. Moreover, the start time of vulcanization increases by almost 300%, the optimal curing time by 200%.

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Studies on the Modification of Commercial Bisphenol-A-Based Epoxy Resin Using Different Multifunctional Epoxy Systems

Applied Mechanics ◽

10.3390/applmech2020023 ◽

2021 ◽

Vol 2 (2) ◽

pp. 419-430

Author(s):

Ankur Bajpai ◽

James R. Davidson ◽

Colin Robert

Keyword(s):

Mechanical Properties ◽

Glass Transition ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Bisphenol A ◽

Epoxy Resin ◽

Tensile Fracture ◽

Chemical Structures ◽

Amino Phenol ◽

Epoxy Systems

The tensile fracture mechanics and thermo-mechanical properties of mixtures composed of two kinds of epoxy resins of different chemical structures and functional groups were studied. The base resin was a bi-functional epoxy resin based on diglycidyl ether of bisphenol-A (DGEBA) and the other resins were (a) distilled triglycidylether of meta-amino phenol (b) 1, 6–naphthalene di epoxy and (c) fluorene di epoxy. This research shows that a small number of multifunctional epoxy systems, both di- and tri-functional, can significantly increase tensile strength (14%) over neat DGEBA while having no negative impact on other mechanical properties including glass transition temperature and elastic modulus. In fact, when compared to unmodified DGEBA, the tri-functional epoxy shows a slight increase (5%) in glass transition temperature at 10 wt.% concentration. The enhanced crosslinking of DGEBA (90 wt.%)/distilled triglycidylether of meta-amino phenol (10 wt.%) blends may be the possible reason for the improved glass transition. Finally, the influence of strain rate, temperature and moisture were investigated for both the neat DGEBA and the best performing modified system. The neat DGEBA was steadily outperformed by its modified counterpart in every condition.

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Effect of reduced graphene oxide on mechanical behavior of an epoxy adhesive in glassy and rubbery states

Journal of Composite Materials ◽

10.1177/00219983211031659 ◽

2021 ◽

pp. 002199832110316

Author(s):

Ata Khabaz-Aghdam ◽

Bashir Behjat ◽

EAS Marques ◽

RJC Carbas ◽

Lucas FM da Silva ◽

...

Keyword(s):

Graphene Oxide ◽

Glass Transition ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Ambient Temperature ◽

Mechanical Behavior ◽

Reduced Graphene Oxide ◽

Epoxy Adhesive ◽

Ultimate Strain ◽

Reduced Graphene

The mechanical behavior of an adhesive, in neat state and reinforced with up to 0.5 wt% of reduced graphene oxide (RGO) was investigated here. Tests were done at temperatures between the ambient temperature and the glass transition temperature ( Tg[Formula: see text] of the adhesive. Using a metal mold, cured plates of the neat and RGO reinforced epoxy adhesive were prepared. The adhesive powder and the bulk dumbbell-shaped specimens, obtained from cured adhesive plates, were subjected to differential scanning calorimetry (DSC) and tensile tests, respectively, to obtain the Tg as well as mechanical properties of the adhesives. The results indicated that adding RGO up to 0.5 wt% increased the glass transition temperature, the modulus of elasticity, and the strength of the adhesive. It was found that the presence of RGO reduced the adhesive’s strain at the break at the ambient temperature. However, at high temperatures, near the Tg, the ultimate strain of RGO-reinforced adhesives decreased slightly when compared to the ultimate strain of the neat specimens. This explains the reduction in toughness at ambient temperature obtained by adding RGO and the increase at high temperatures. Finally, the failure morphology of the neat and RGO-reinforced adhesive specimens was investigated using microscopic imaging of the specimens’ failure cross-sections, which supported and justified the experimental observations.

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Synthesis, Properties, and Biodegradability of Thermoplastic Elastomers Made from 2-Methyl-1,3-propanediol, Glutaric Acid and Lactide

Life ◽

10.3390/life11010043 ◽

2021 ◽

Vol 11 (1) ◽

pp. 43

Author(s):

Lamya Zahir ◽

Takumitsu Kida ◽

Ryo Tanaka ◽

Yuushou Nakayama ◽

Takeshi Shiono ◽

...

Keyword(s):

Mechanical Properties ◽

Glass Transition ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Glutaric Acid ◽

Triblock Copolymers ◽

Tensile Tests ◽

Thermoplastic Elastomers ◽

Proteinase K ◽

Synthesis Properties

An innovative type of biodegradable thermoplastic elastomers with improved mechanical properties from very common and potentially renewable sources, poly(L-lactide)-b-poly(2-methyl-1,3-propylene glutarate)-b-poly(L-lactide) (PLA-b-PMPG-b-PLA)s, has been developed for the first time. PLA-b-PMPG-b-PLAs were synthesized by polycondensation of 2-methyl-1,3-propanediol and glutaric acid and successive ring-opening polymerization of L-lactide, where PMPG is an amorphous central block with low glass transition temperature and PLA is hard semicrystalline terminal blocks. The copolymers showed glass transition temperature at lower than −40 °C and melting temperature at 130–152 °C. The tensile tests of these copolymers were also performed to evaluate their mechanical properties. The degradation of the copolymers and PMPG by enzymes proteinase K and lipase PS were investigated. Microbial biodegradation in seawater was also performed at 27 °C. The triblock copolymers and PMPG homopolymer were found to show 9–15% biodegradation within 28 days, representing their relatively high biodegradability in seawater. The macromolecular structure of the triblock copolymers of PLA and PMPG can be controlled to tune their mechanical and biodegradation properties, demonstrating their potential use in various applications.

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Silane Functionalized Ethylene/Diene Copolymer Modifiers in Composites of Heterophasic Polypropylene and Microsilica

Polymers and Polymer Composites ◽

10.1177/096739110701500501 ◽

2007 ◽

Vol 15 (5) ◽

pp. 343-355 ◽

Cited By ~ 1

Author(s):

S. Lipponen ◽

P. Pietikäinen ◽

U. Vainio ◽

R. Serimaa ◽

J.V. Seppälä

Keyword(s):

Glass Transition ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Impact Strength ◽

Ambient Temperature ◽

Metallocene Catalyst ◽

The Poor ◽

Rubber Toughened ◽

Rubbery Phase ◽

The Impact

Ethylene/1,7-octadiene copolymer was polymerised with metallocene catalyst and hydrosilylated to form silane functionalised polyethylenes (PE-co-SiX, X=Cl, OEt, Ph). The functionalised species were tested as modifiers in composites of rubber toughened polypropylene (heterophasic PP, hPP) and microsilica filler (μSi). A metallocene-based functionalised PE (PE-co-SiF) produced earlier in our laboratory and three commercial grades of functionalised polyolefins (one PE- and two PP-based) were used as reference modifiers. Major differences were seen in the toughness of the composites both above and below the glass transition temperature (Tg) of PP. In addition to increasing the stiffness, the microsilica filler enhanced the toughness of the heterophasic polypropylene by over 200% at ambient temperature. Below the Tg of PP (at −20 °C), the influence of μSi was the opposite and the impact strength of the hPP/μSi composite was below that of unfilled hPP. With the addition of just 2 wt% of functionalised polyethylene, the poor cold toughness of hPP/μSi composite was improved by nearly 100%. With the same addition, the toughness of the composites at ambient temperature was improved by 50 to 100% compared with the unfilled hPP. This behaviour was explained by significant changes in the fracture mechanism. Addition of functionalised PE increased the concentration of microsilica in the rubbery phase, allowing the crack to enter that phase. The rubbery phase was also able to absorb a large amount of impact energy below the glass transition temperature of PP.

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