Structure–property relationships of poly(urethane–urea)s with ultra-low monol content poly(propylene glycol) soft segments. Part II. Influence of low molecular weight polyol components

Polymer ◽  
2002 ◽  
Vol 43 (26) ◽  
pp. 7399-7408 ◽  
Author(s):  
Matthew J O'Sickey ◽  
Bruce D Lawrey ◽  
Garth L Wilkes
Keyword(s):  
Molecular Weight ◽  
Propylene Glycol ◽  
Low Molecular Weight ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Soft Segments ◽  
Poly Propylene

SYNTHESIS AND CHARACTERIZATION OF FARNESENE-BASED POLYMERS

2017 ◽  
Vol 90 (2) ◽  
pp. 308-324 ◽  
Author(s):  
Taejun Yoo ◽  
Steven K. Henning
Keyword(s):  
Molecular Weight ◽  
Anionic Polymerization ◽  
Molar Mass ◽  
Functional Materials ◽  
Synthesis And Characterization ◽  
Low Molecular Weight ◽  
Structure Property ◽  
Structure Property Relationships ◽  
By Products

ABSTRACT A bio-based route to the production of trans-β-farnesene has recently been commercialized. Trans-β-farnesene is capable of being polymerized by both anionic and cationic pathways, creating low molecular weight polymers with structure–property relationships unique within the diene class of monomers. Trans-β-farnesene is produced through fermentation of sugar feedstocks. The pathway offers an alternative to petroleum-based feedstocks derived as by-products of naphtha or ethane cracking. Anionic polymerization of the monomer produces a highly branched “bottlebrush” structure, with rheological properties that are markedly different than those of linear diene polymers. Specifically, a lack of entanglements is observed even at relatively high molar masses. For hydroxyl-terminated oligomers, Tg as a function of molar mass follows a trend opposite non-functional materials. The synthesis and characterization of trans-β-farnesene–based polymers will be presented, including anionically prepared low molecular weight diols and monols.

Crosslinking and Mechanical Properties of Liquid Rubber. I. Curative Effect of Aliphatic DIOLS

1979 ◽  
Vol 52 (5) ◽  
pp. 920-948 ◽  
Author(s):  
Yuji Minoura ◽  
Shinzo Yamashita ◽  
Hiroshi Okamoto ◽  
Tadao Matsuo ◽  
Michiaki Izawa ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Low Molecular Weight ◽  
Structure Property ◽  
X Ray Diffraction ◽  
Curative Effect ◽  
Polyurethane Elastomers ◽  
X Ray ◽  
Structure Property Relationships ◽  
The Difference

Abstract The structure-property relationships of polyurethane elastomers derived from a liquid hydroxyl-terminated polybutadiene/low molecular weight aliphatic diol/diisocyanate system were studied. The effects of the amount of low molecular weight diol on the mechanical properties of the elastomer were discussed on the basis of the results of stress-strain, swelling, dynamic viscoelasticity, x-ray diffraction, etc. It was found that some particular combinations of low molecular weight diol and diisocyanate specifically affect the properties of elastomers. When the mechanical properties of the elastomers were plotted against the number of methylene carbons in the low molecular weight diol, characteristic zigzag patterns were obtained. These patterns were explained by the difference in the packing and the dependence of the strength of intermolecular hydrogen bonding on whether the number of the methylene carbons was even or odd. This assumption was confirmed by x-ray diffraction.

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.

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