scholarly journals Hydrogen bonding and thermoplastic elastomers – a nice couple with temperature-adjustable mechanical properties

Soft Matter ◽  
2018 ◽  
Vol 14 (14) ◽  
pp. 2701-2711 ◽  
Author(s):  
Elisabeth Wittenberg ◽  
Andreas Meyer ◽  
Steffen Eggers ◽  
Volker Abetz
Keyword(s):  
Mechanical Properties ◽  
Hydrogen Bonding ◽  
Thermoplastic Elastomers ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Styrene Butadiene ◽  
Hydrogen Bonded

Hydrogen bonded supramolecular styrene–butadiene copolymers are investigated regarding their structure–property relationships using DSC, DMA, FTIR and SAXS.

New Polybutadiene-Based Thermoplastic Elastomers: Synthesis, Morphology and Mechanical Properties

1997 ◽  
Vol 70 (5) ◽  
pp. 714-726 ◽  
Author(s):  
Ph Dubois ◽  
Y. S. Yu ◽  
Ph Teyssié ◽  
R. Jérôme
Keyword(s):  
Mechanical Properties ◽  
Thermoplastic Elastomers ◽  
Butyl Methacrylate ◽  
Structure Property ◽  
Thermal Transitions ◽  
Selective Hydrolysis ◽  
Structure Property Relationships ◽  
Meth Acrylic Acid ◽  
Hydrolysis Of ◽  
Butadiene Styrene

Abstract Well defined poly[styrene-b-butadiene-b-styrene] block copolymers (SBS) end-capped with poly(t-butyl methacrylate) (PtBMA) and poly (meth acrylic acid) (PMA) outer blocks, respectively, have been synthesized by the sequential anionic polymerization of butadiene, styrene and tBMA, followed by the selective hydrolysis of the PtBMA blocks into the corresponding PMA blocks. The structure-property relationships of these new thermoplastic elastomers have been investigated, with a special emphasis on the effect of the ester or acid outer blocks on the bulk properties. As a rule, tensile strength is improved by increasing the length of the ester or acid outer blocks from 0 to 140 methacrylic units. Dipole—dipole intermolecular interaction of the PtBMA blocks and hydrogen bonding of the PMA blocks may account for enhanced mechanical properties. However, too high a degree of strong intermolecular interactions can constitute a deterrent to good phase separation. This is supported by morphological observations and loss in tensile properties when the relative content of the ester or acid outer blocks exceeds some critical value. In the case of a high acid content, DSC analysis shows two thermal transitions at −70 °C and 230°C for PBD and PMA blocks, respectively.

QSPR STUDY OF RHEOLOGICAL AND MECHANICAL PROPERTIES OF CHLOROPRENE RUBBER ACCELERATORS

2014 ◽  
Vol 87 (2) ◽  
pp. 219-238 ◽  
Author(s):  
Roberto Todeschini ◽  
Viviana Consonni ◽  
Davide Ballabio ◽  
Andrea Mauri ◽  
Matteo Cassotti ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mathematical Models ◽  
Structural Features ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Quantitative Structure Property Relationships ◽  
Cure Time ◽  
Chloroprene Rubber ◽  
Experimental Values ◽  
Rubber Accelerators

ABSTRACT In this preliminary study, mathematical models based on Quantitative Structure Property Relationships (QSPR) were applied in order to analyze how molecular structure of chloroprene rubber accelerators relates to their rheological and mechanical properties. QSPR models were developed in order to disclose which structural features mainly affect the mechanism of vulcanization. In such a way QSPR can help in a faster and more parsimonious design of new chloroprene rubber curative molecules. Regression mathematical models were calibrated on two rheological properties (scorch time and optimum cure time) and three mechanical properties (modulus 100%, hardness, and elongation at break). Models were calculated using experimental values of 14 accelerators belonging to diverse chemical classes and validated by means of different strategies. All the derived models gave a good degree of fitting (R2 values ranging from 84.5 to 98.7) and a satisfactory predictive power. Moreover, some hypotheses on the correlations between specific structural features and the analyzed rheological and mechanical properties were drawn. Owing to the relatively small set of accelerators used to calibrate the models, these hypotheses should be further investigated and proved.

Heat Aging Behavior of Novel Poly (Phenylene-Ether) Based Thermoplastic Elastomers

2008 ◽  
Vol 81 (2) ◽  
pp. 244-264 ◽  
Author(s):  
Samik Gupta ◽  
Radha Kamalakaran ◽  
Avdhut Maldikar ◽  
Ashok Menon ◽  
Anil K. Bhowmick
Keyword(s):  
Mechanical Properties ◽  
Thermal Degradation ◽  
Vinyl Acetate ◽  
Degradation Mechanism ◽  
Ethylene Vinyl Acetate ◽  
Thermoplastic Elastomers ◽  
Chemical Degradation ◽  
Modulated Dsc ◽  
Structure Property ◽  
Aging Performance

Abstract The heat aging performance of a series of novel poly (phenylene ether) (PPE) based thermoplastic elastomers (TPEs) from styrene-ethylene-butylene-styrene (SEBS), ethylene vinyl acetate (EVA) and PPE-polystyrene (PS), was studied. This quaternary blend showed superior heat aging performance due to the high Tg thermoplastic component (PPE). At 80 °C, different compositions of the quaternary blends were exposed for 500 hours. Effects of compositions, vinyl acetate (VA) content of EVA and different molecular weights (MW) of SEBS, on the mechanical properties upon heat aging were analyzed in detail. A representative composition (based on the mechanical properties) of the quaternary blend (SEBS/EVA/PPE-PS: 45/30/25) was exposed at different temperatures, i.e. 80 °C, 120 °C, 140 °C and 170 °C, for 2000 hours. Thermal degradation profiles of change in tensile strength and percent elongation at break due to thermal degradation of the blends were monitored and “half-life” temperature was estimated. Using the Arrhenius equation, the “lifetime” of the quaternary blend was predicted (100,000 hours at ∼131 °C). Change in functionalities due to chemical degradation was also monitored using Fourier Transform Infrared Spectroscopy (FTIR). As a consequence of degradation, the shift in Tg was observed by temperature modulated DSC (Differential Scanning Calorimeter). Detailed microstructural studies were done to establish the structure-property correlation, for degraded as well as pristine materials. The degradation mechanism was elucidated on the basis of morphology and structure studies of the blends.

Insights into Sulfur Vulcanization from QSPR Quantitative Structure-Property Relationships Studies

1999 ◽  
Vol 72 (2) ◽  
pp. 318-333 ◽  
Author(s):  
Fred Ignatz-Hoover ◽  
Alan R. Katritzky ◽  
Victor S. Lobanov ◽  
Mati Karelson
Keyword(s):  
Molecular Descriptors ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Structure Property ◽  
Concerted Mechanism ◽  
Structure Property Relationships ◽  
Quantitative Structure Property Relationships ◽  
Crosslinking Reactions ◽  
Styrene Butadiene ◽  
Aromatic Heterocyclic

Abstract Vulcanization of styrene-butadiene rubber, as accelerated by a series of sulfenamides and sulfenimides prepared from various aromatic heterocyclic thiols and various aliphatic amines, was studied using the curemeter under isothermal conditions. Further studies using MOPAC AM1 semiempirical quantum mechanical calculations and CODESSA QSAR software yielded excellent correlations of molecular descriptors of accelerators or accelerator thiolate zinc complexes to the onset of cure and maximum rate of vulcanization. The QSAR results support previously proposed mechanisms describing the origin of scorch delay for the delayed action, fast curing sulfenamide accelerators. In addition, the results support a carbanionic concerted mechanism for the sulfurization and crosslinking reactions.

Structure–Property Relationships in Hydrogen-Bonded Liquid Crystals

2017 ◽  
Vol 29 (19) ◽  
pp. 8462-8471 ◽  
Author(s):  
Michael Pfletscher ◽  
Sandra Hölscher ◽  
Christoph Wölper ◽  
Markus Mezger ◽  
Michael Giese
Keyword(s):  
Liquid Crystals ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Hydrogen Bonded
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