SILANE-TERMINATED LIQUID POLY(BUTADIENES) IN TREAD FORMULATIONS: A MECHANISTIC STUDY

2020 ◽  
pp. 000-000
Author(s):  
Fabien Salort ◽  
Steven K. Henning
Keyword(s):  
Molecular Weight ◽  
Viscoelastic Behavior ◽  
Mechanistic Study ◽  
Structure Property ◽  
Silane Coupling Agents ◽  
Chain Entanglement ◽  
Molecular Weights ◽  
Structure Property Relationships ◽  
Silane Coupling ◽  
History Of

ABSTRACT Liquid poly(butadienes) are materials that exhibit flow properties as their molecular weights are at or below that for significant chain entanglement. When applied to tire compound formulation in additive amounts, these low-molecular-weight oligomers are compatible with the elastomeric phase and can influence viscoelastic behavior. The present article will catalogue the history of the use of liquid poly(butadiene) materials in tire compounding, linking their varied application to the evolution of structure–property relationships as a function of microstructure changes. The result of this evolution is the commercialization of functionalized liquid polybutadienes, specifically silane-terminated grades designed for silica-filled systems. It has been found that these materials are not replacements for the typical silane coupling agents ubiquitously used in silica formulating but are rather synergistic with the established technology. The application of silane-terminated liquid poly(butadienes) can both improve traction indicators and limit the negative hysteresis effect commonly associated with the use of liquid poly(butadiene) resins. The mechanism behind the specific changes in viscoelastic and mechanical properties attributed to the addition of silane-terminated liquid poly(butadienes) is explored. It is found that the terminal silane function of the liquid poly(butadienes) may both interact with the silane coupling agent–modified surface of the dispersed silica particles and be available to condense with each other, forming a higher-molecular-weight structure that may effectively increase the apparent crosslink density and therefore bound rubber as an interpenetrating network that extends well into the elastomer phase.

Mechanical and Viscoelastic Characterization of Hyperbranched Polyisobutylenes

2002 ◽  
Vol 75 (5) ◽  
pp. 853-864 ◽  
Author(s):  
Judit E. Puskas ◽  
Christophe Paulo ◽  
Volker Altstädt
Keyword(s):  
Molecular Weight ◽  
Butyl Rubber ◽  
Structure Property ◽  
Carbocationic Polymerization ◽  
Molecular Weights ◽  
Structure Property Relationships ◽  
Molecular Weight Distributions ◽  
Weight Distributions ◽  
Living Carbocationic Polymerization

Abstract Structure-property relationships were investigated in hyperbranched polyisobutylenes, in comparison with commercial linear butyl rubber. The gel-free, soluble hyperbranched polyisobutylenes, synthesized by living carbocationic polymerization, had molecular weights, Mw≈400,000 to 1,000,000 g/mol, molecular weight distributions, MWD ≈1.2 to 2.6, and branching frequencies, BR ≈ 4 to 60. The mechanical and viscoelastic characterization of these polymers revealed interesting properties, including the characteristics of crosslinked rubbers.

scholarly journals Hyperbranched Silicone MDTQ Tack Promoters

Molecules ◽  
2019 ◽  
Vol 24 (22) ◽  
pp. 4133 ◽  
Author(s):  
Sijia Zheng ◽  
Shuai Liang ◽  
Yang Chen ◽  
Michael A. Brook
Keyword(s):  
Molecular Weight ◽  
Phase Separation ◽  
Complex Mixtures ◽  
Low Molecular Weight ◽  
Structure Property ◽  
Chain Entanglement ◽  
Silicone Gel ◽  
Structure Property Relationships ◽  
Branch Density

Low molecular weight, highly crosslinked silicone resins are widely used as reinforcing agents for highly transparent elastomers and adhesion/tack promoters in gels. The resins are complex mixtures and their structure / property relationships are ill defined. We report the synthesis of a library of 2, 3 and 4-fold hyperbranched polymeric oils that are comprised of linear, lightly branched or highly branched dendronic structures. Rheological examination of the fluids and tack measurements of gels filled with 10, 25 or 50% dendronic oils were made. Viscosity of the hyperbranched oils themselves was related to molecular weight, but more significantly to branch density. The properties are driven by chain entanglement. When cured into a silicone gel, less densely branched materials were more effective in improving tack than either linear oils or Me3SiO-rich, very highly branched oils of comparable molecular weight, because the latter oils underwent phase separation.

Dependence of Tack Strength on Molecular Properties

1959 ◽  
Vol 32 (1) ◽  
pp. 48-66 ◽  
Author(s):  
W. G. Forbes ◽  
L. A. McLeod
Keyword(s):  
Molecular Weight ◽  
Shear Viscosity ◽  
Catalyst System ◽  
Chain Entanglement ◽  
Molecular Weights ◽  
Styrene Copolymers ◽  
The Difference ◽  
Catalyst Systems ◽  
Time Required ◽  
Butadiene Styrene

Abstract A method has been developed for the measurement of the tack strength of fresh and reproducibly smooth rubber surfaces. Using this method the tack strength of natural rubber is shown to be independent of polymer purity, and, to a large extent, Mooney viscosity, intrinsic viscosity, gel content and molecular weight distribution. The relative tack strengths of polyisoprenes of different molecular weights prepared in different catalyst systems are measured. The results are discussed in terms of microstructure. A study of the tack strength of oil-extended butadiene-styrene copolymers indicates that relative tack strength is related to the shear viscosity of the bulk polymer. Measurements of relative tack strength on Alfin and free radical butadiene-styrene copolymers, butyl, brominated butyl and butadiene-acrylonitrile copolymers confirm the inportance of shear viscosity in controlling tack strength. Choice of catalyst system and temperature of polymerization cause the largest variation in polymer viscosity. The contact time required for the relative tack strength to become unity is shown to be inversely dependent upon the value of the relative tack strength itself. Shear viscosity measurements are given for six classes of polymer and the values shown to correlate with relative tack strength. It is postulated that molecular weight (and probably also chain entanglement) is the controlling variable. The bond strength between two different uncured polymers is shown to depend upon the difference in cohesive energy densities of the two polymers.

Polyetherimides—synthesis and structure-property relationships

1993 ◽  
Vol 5 (1) ◽  
pp. 37-45 ◽  
Author(s):  
Martin Davies ◽  
John N Hay ◽  
Barry Woodfine
Keyword(s):  
Molecular Weight ◽  
Glass Transition ◽  
Thermal Properties ◽  
Structure Property ◽  
Polymer Molecular Weight ◽  
Chain Flexibility ◽  
Structure Property Relationships ◽  
Polymer Properties ◽  
Synthetic Routes ◽  
Rotational Freedom

Polyetherimides have been synthesized by two complementary routes starting from 4-halophthalic anhydride. A range of polymers has been prepared by varying the structure of the diamines and bisphenols employed in the syntheses. These polymers have been characterized by their m spectra, molecular weight and thermal properties. The applicability and limitations of the synthetic routes are discussed. Structure-property (glass transition temperature, Tg relationships are elucidated and discused in terms of the structural fragments in the polymer chain. Chain flexibility, rotational freedom and inter-chain interactions are all important parameters affecting the polymer properties. The effect of polymer molecular weight on Tg is also discussed.

Investigation of the Structure-Property Relationships of Improved Low Compression Set Nitrile Rubbers

1981 ◽  
Vol 54 (1) ◽  
pp. 170-180 ◽  
Author(s):  
D. M. Chang
Keyword(s):  
Molecular Weight ◽  
Physical Properties ◽  
Structure And Properties ◽  
Structure Property ◽  
Compression Set ◽  
Structure Property Relationships ◽  
Polymer Properties ◽  
Nitrile Rubbers ◽  
New Type ◽  
The Right

Abstract The effect of polymer structures on the rubber processing and physical properties of the improved Hycar 1090 low compression set nitrile rubbers was investigated. The molecular weight and acrylonitrile content of a polymer are important variables in determining the compound processing and vulcanizate physical properties. Within the range of 21 to 88 Mooney, a blend of high and low Mooney polymers has approximately the same properties as those from a single polymer of the same Mooney viscosity. The molecular weight distribution was not significantly broadened to become an important factor affecting the polymer properties. All polymers with Mooney viscosities from 21 to 88 showed good properties. An understanding of the structure and properties of this new type of NBR, will help in choosing the right kind of polymer for particular applications.

scholarly journals Physical and Electrochemical Properties of Soluble 3,4-Ethylenedioxythiophene (EDOT)-Based Copolymers Synthesized via Direct (Hetero)Arylation Polymerization

2021 ◽  
Vol 9 ◽  
Author(s):  
Qiang Guo ◽  
Jincheng Zhang ◽  
Xiaoyu Li ◽  
Heqi Gong ◽  
Shuanghong Wu ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Electrochemical Properties ◽  
High Performance ◽  
Molecular Conformation ◽  
Careful Study ◽  
Structure Property ◽  
Organic Electronic Devices ◽  
Molecular Weights ◽  
Structure Property Relationships ◽  
Electronic And Structural Properties

Over the past decades, π-conjugated polymers (CPs) have drawn more and more attention and been essential materials for applications in various organic electronic devices. Thereinto, conjugated polymers based on the 3,4-ethylenedioxythiophene (EDOT) backbone are among the high-performance materials. In order to investigate the structure–property relationships of EDOT-based polymers and further improve their electrochemical properties, a series of organic solvent–soluble EDOT-based alternative copolymers consisting of electron-rich fragments (fluorene P1, carbazole P2, and 3,4-alkoxythiophene P3) or electron-deficient moieties (benzotriazole P4 and thieno[3,4-c]pyrrole-4,6-dione P5) were synthesized via direct C–H (hetero)arylation polymerization (DHAP) in moderate to excellent yields (60–98%) with medium to high molecular weights (Mn = 3,100–94,000 Da). Owing to their various electronic and structural properties, different absorption spectra (λmax = 476, 380, 558, 563, and 603 nm) as well as different specific capacitances of 70, 68, 75, 51, and 25 F/g with 19, 10, 21, 26, and 69% of capacity retention after 1,000 cycles were observed for P1–P5, respectively. After careful study through multiple experimental measurements and theoretical calculation, appropriate electronic characteristics, small molecular conformation differences between different oxidative states, and well-ordered molecular stacking could improve the electrochemical performance of CPs.

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