Hydrophobic, Water-Dispersible Polyurethane: Role of Polybutadiene Diol Structure

Abstract

Preparation of stable, free-standing elastic film with hydrophobic surface from water dispersible polyurethanes (WDPUs) is a challenging task. Here, we have prepared WDPUs from polybutadiene based diols and the resulting PU films are satisfying the requisites. Two types of diols namely hydroxyl terminated polybutadiene (HTPB) and terminal functionalized HTPB with dinitrobenzene (DNB) [HTPB-DNB] were used to make WDPUs and the effects of diol structures were investigated. The synthesized WDPUs displayed particle morphology with size in the range of ~130-270 nm and more than one year storage stability. WDPUs yielded stable and free standing films upon curing and the resulting films showed high thermal and mechanical stabilities. The contact angle of the films is in the range of ~ 80-100° attributing the hydrophobic nature of the surface. Hard segment content of the PU was varied from 30-40 % (by weight) to tune the properties of WDPUs and the resulting films.

Triazine functionalized hydroxyl terminated polybutadiene polyurethane: Influence of triazine structure

“…However, it is very difficult to improve both tensile strength (s b ) and elongation at break ( 3 b ) simultaneously. Recently, we are successful in increasing both tensile strength (s b ) and elongation at break ( 3 b ) of PUs simultaneously by terminal functionalization of HTPB with dinitrophenyl group as functional moiety [42,43,47]. In this present study, we are extending our earlier observation for further understanding the effect of terminal functionalization of HTPB especially on mechanical properties along with other properties of PUs.…”

“…The stoichiometric ratio between the functional groups (ÀNCO/ÀOH) was maintained constant and equal to 1:1 for all PUs synthesis. The moles of eOH functionality are calculated from the hydroxyl values of HTPB and modified HTPB [42,43,46]. It is to be noted that all the reaction conditions and curing conditions for the preparation of all twelve PUs are exactly identical.…”

“…Several approaches have been established in literature by which either 3 b or s b of PUs can be improved. For example, the increase in NCO/OH ratio or hard segment content (HSC) often enhances the tensile strength; on the other hand increase in the soft segment content results into higher ε b [42,43,46]. However, it is very difficult to improve both tensile strength (s b ) and elongation at break ( 3 b ) simultaneously.…”

“…Very recently, an experiment to improve both the strength and elongation of HTPB based PUs with the help of an aromatic functional moiety namely dinitrobenzene (DNB) which is chemically attached at the terminal carbons of HTPB and is capable of introducing hydrogen bonding between the hard and soft segments of HTPB-PUs was successful [42,43]. It was proved that the nitro functionality of dinitrobenzene is responsible for segmental mixing through hydrogen bonding interactions which in turn improves tensile strength and elongation simultaneously.…”

Hydrolysis‐resistant polyurethane elastomers synthesized from hydrophobic bio‐based polyfarnesene diol

“…This excellent hydrophobicity is caused by the long aliphatic hydrocarbon main chains and branched alkyl side chains with lengths of C11 and C13 in PFD. Moreover, this unique “bottle brushes” structure enables PFD‐based PUEs exhibit higher water contact angle than relative linear HTPB‐based PUEs, of which the water contact angle was about 90° …”