Effect of different monomer precursors with identical functionality on the properties of the polymer network

AbstractThe association between thermo-mechanical properties in polymers and functionality of monomer precursors is frequently exploited in the materials science. However, it is not known if there are more variables beyond monomer functionality that have a similar link. Here, by using simulations to generate spatial networks from chemically different monomers with identical functionality we show that such networks have universal graph-theoretical properties as well as a near-universal elastic modulus. The vitrification temperature was found to be universal only up to a certain network density, as measured by the bond conversion. The latter observation is explained by the fact that monomer’s tendency to coil enhances formation of topological holes, which, when accumulated, amount to a percolating cell complex restricting network’s mobility. This higher-order percolation occurs late after gelation and is shown to coincide with the onset of brittleness, as indicated by a sudden increase in the glass transition temperature.

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Mechanical properties of nylon 6-clay hybrid

Journal of Materials Research ◽

10.1557/jmr.1993.1185 ◽

1993 ◽

Vol 8 (5) ◽

pp. 1185-1189 ◽

Cited By ~ 1820

Author(s):

Yoshitsugu Kojima ◽

Arimitsu Usuki ◽

Masaya Kawasumi ◽

Akane Okada ◽

Yoshiaki Fukushima ◽

...

Keyword(s):

Mechanical Properties ◽

Glass Transition ◽

Elastic Modulus ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Loss Modulus ◽

Nylon 6 ◽

Heat Distortion Temperature ◽

Molecular Composites ◽

Silicate Layers

Various nylon 6-clay hybrids, such as molecular composites of nylon 6 and silicate layers of montmorillonite and saponite, NCH's and NCHP's, respectively, have been synthesized. To estimate the mechanical properties of these hybrids, tensile, flexural, impact, and heat distortion tests were carried out. NCH was found superior in strength and modulus and comparable in impact strength to nylon 6. The heat distortion temperature (HDT) of NCH (montmorillonite: 4.7 wt. %) was 152 °C, which was 87 °C higher than that of nylon 6. In NCHP, saponite had a smaller effect on the increase of these mechanical properties. The modulus and HDT of NCH and NCHP increased with an increase in the amount of clay minerals. It was found that these properties were well described by the contribution of the constrained region calculated from the storage and loss modulus at the glass transition temperature. According to the mixing law on elastic modulus, the following expression was obtained between the modulus E at 120 °C and the fraction of the constrained region C, En = Ecn = C, where the values of n and Ec (modulus of the constrained region) were 0.685 and 1.02 GPa, respectively.

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Glass transition temperature and elastic modulusof nanocomposites based on polyimides

Vestnik MGSU ◽

10.22227/1997-0935.2015.6.50-63 ◽

2015 ◽

pp. 50-63

Author(s):

Tat’yana Anatol’evna Matseevich ◽

Marina Nikolaevna Popova ◽

Andrey Aleksandrovich Askadskiy

Keyword(s):

Mechanical Properties ◽

Glass Transition ◽

Elastic Modulus ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Chemical Structure ◽

Van Der Waals Volume ◽

Polar Groups ◽

Wide Range ◽

Nanoparticles Concentration

Today great attention is paid to production and research of the mechanical and termal properties of nanocomposites based on polyimides. These polymers are heatresisting and possess the increased mechanical properties in wide range of temperatures. Various nanoparticles are introduced into polyimides: graphite nanotubes and flatparticles, the particles of SiO , the surface of which is modified, the particles of ZrOandmontmorillonite, etc.The authors analyzed the influence of nanoparticles on the glass transition temper-ature T and elastic modulus E of the polyimides based on 1,3-bis-(3,3’,4,4’-dicarboxy-phenoxy)benzene and 4,4’-bis-(4-aminophenoxy)biphenyl, and pyromellitic dianhydride and oxydianiline. Nanoparticles introduced in small amounts are produced of graphite and ZrO . The suggested ratios take into account the chemical structure of the polymer and nanoparticles, as well as the structure of their surface in case of chemical modification; the concentration of nanoparticles and their form, the number of polar groups on the surface. The number of polar groups and nanoparticles’ concentration have the greatest influence on T . The elastic modulus of nanocomposites depending on nanoparticles’ concentration is connected with van der Waals volume of the repeating unit of polymer and nanoparticle.

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Determination of Thermo-Mechanical Properties of Recycled Polyurethane From Glycolysis Polyol

International Journal of Manufacturing Materials and Mechanical Engineering ◽

10.4018/ijmmme.2021100105 ◽

2021 ◽

Vol 11 (4) ◽

pp. 75-87

Author(s):

James Njuguna ◽

Peter Muchiri ◽

Nancy Karuri ◽

Fredrick Madaraka Mwema ◽

Michael T. Herzog ◽

...

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Glass Transition ◽

Elastic Modulus ◽

Transition Temperature ◽

Hardness Test ◽

Raw Material ◽

Glass Transition Temperatures ◽

D Values

This study aimed to determine the possible changes in thermo-mechanical properties between recycled polyurethane with benchmark polyurethane. The glycolysis polyol was used as a raw material for recycled polyurethane production. The glass transition temperature of the recycled polyurethane was determined using DSC. Tensile strength, elastic modulus, toughness, and hardness test of the recycled polyurethane were conducted at 24°C, 40°C, and 60°C. The glass transition temperatures for the recycled and the benchmark polyurethane occurred at 43°C and 50.4°C, respectively. Tensile strength for recycled polyurethane was lower than that of benchmark polyurethane by 29-43%. Recycled polyurethane recorded lower toughness than petroleum-based pure polyurethane by 13-16%. However, recycled polyurethane recorded high shored D values than the benchmark polyurethane by 9-29%. This study reveals that recycled polyol could be used as feedstock for polyurethane production with applications tailored to its mechanical properties.

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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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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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