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Temperature responsive polymers able to alter their chemical or physical properties have been extensively investigated. Most of these polymers have an alkane polymer backbone with only carbon-carbon bonds. In this sense, the design of thermoresponsive polymers not only with sharp transition temperatures but also possessing hydrolizable linkages such as esters, carbonates or urethanes in the main backbone...
Polyurethanes grafted with well-defined polar pendants were synthesized and investigated. A series of linear and dendritic poly(urea/malonamide)s with uniform chain length were first prepared from an iterative synthesis route, which is based on a dual-functional building block, 4-isocyanate-4´-(3,3-dimethyl-2,4-dioxo-azetidine)diphenyl methane (IDD). Moreover, side chain polyurethanes (SPUs) bearing...
The relaxation behavior of a series of solvent free polyurethane model networks with variable cross-link density prepared based on different commercial diols and a diisocyanate containing component are studied by differential scanning calorimetry (DSC), dynamic-mechanical analysis (DMA) and dielectric relaxation spectroscopy (DRS). A systematic decrease of the calorimetric glass temperature Tg as...
An efficient route to obtain allyl- and propargyl-containing diols from 10-undecen-1-ol, and their polymerization with isophorone diisocyanate to produce alkene- and alkyne-functionalized polyurethanes (PUs) is described. The bio-based PUs have been further modified by thiol-ene/yne coupling of thioglycerol into unsaturation to obtain a series of PUs with enhanced hydrophilicity. All the synthesized...
Segmented thermoplastic polyurethanes, polyureas and polyurethaneureas (TPU) based on a given hard segment and two chemically different soft segments display interesting microphase morphologies and thermal, mechanical and surface properties. In these systems the final TPU morphology is mainly controlled by the structure, amount and molecular weight of the soft segment oligomers and the nature and...
Three polyurethanes (PRX1500Me-PU, PRX4000Me-PU, and PRX6000Me-PU) crosslinked by polyrotaxanes (PRXs), which consist of half-methylated α-cyclodextrins (CyDs) and poly(oxyethylene)glycols with different chain lengths (PEG1500, PEG4000, and PEG6000), were synthesized. The filling ratios of CyD in PRX1500, PRX4000 and PRX6000 are 75, 63 and 37%, respectively. A polyurethane crosslinked by half-methylated...
We have successfully synthesized novel polyurethanes where PU1 contains a [3]rotaxane that consists of N-3,5-di-tert-butylbenzyl-N-3-hydroxypropylammonium hexafluorophosphate (AOH1) and N,N′-Dimethyl-N,N′-bis(dibenzo-24-crown-8)-terephthalamide (BisC) as well as PU2 contains a [2]rotaxane that consists of AOH1 and dibenzo-24-crown-8 ether. Diphenylmethanediisocyanate (MDI), 1,4-butanediol (BD) and...
Ionic liquids (ILs) were fixed into polyether-based polyurethane (PU) films for sustainable antistatic properties. Preliminarily, ILs were screened in terms of efficiency of antistatic effect. Surface resistivity (ρ s ) for IL-doped PU films changed depending the anion species, and the smallest ρ s was found for the PU films containing bis(trifluoromethanesulfonyl)imide ([Tf 2...
A variety of vegetable oil-based, waterborne polyurethane dispersions have been successfully synthesized from different vegetable oil polyols exhibiting almost constant hydroxyl functionalities of 2.7 OH groups per molecule. The vegetable oil polyols, which have been prepared from vegetable oils with different fatty acid compositions (peanut, corn, soybean, and linseed oil), range in residual degree...
In this study, the distributions of hard segment lengths in flexible and viscoelastic polyurethane foams are investigated. To that extent, MALDI spectra of hard segment chains from polyurethane (“PU”) viscoelastic (“Visco”) and conventional flexible (“Flex”) foam series were obtained and analyzed. Results indicate that within each foam series, there was no significant difference at different water...
Elevated environmental consciousness among producers and consumers has resulted in significant interest and research in seed oil derived building blocks for polymer synthesis. While slowly making inroads into selected applications, performance deficits have consistently relegated seed oil derived elastomers to roles having low performance requirements, or where biodegradability is paramount. In this...
In this paper, we report on the shape memory behavior of a family of hardblock-free multiblock thermoplastic polyurethanes (TPUs) consisting of poly(ε-caprolactone) (PCL) and poly(ethylene glycol) (PEG). Due to high molecular weight (M n > 200 kDa), high degrees of entanglement were achieved. Instead of conventional “hard” blocks, entanglements served as the physical crosslinks in this...
Optically active polyurethanes (LPU and DPU) and racemic polyurethane (RPU) were synthesized by the self-polyaddition of the isocyanate-phenols which derived from the chiral and racemic tyrosine. All of the polymers were characterized by FT-IR, 1 H NMR, GPC, UV–Vis spectroscopy, circular dichroism (CD) spectroscopy, TGA and X-ray diffraction (XRD), and the infrared emissivity values were investigated...
Segmented polyurethane (PU) block copolymers were synthesized using 4,4′-methylenediphenyl diisocyanate and 1,4-butanediol as hard segments and oligomeric ethoxypropyl polydimethylsiloxane (PDMS) as the soft segments, with hard segment contents ranging from 26 to 52 wt%. The microphase separated morphology, phase transitions, and degrees of phase separation of these novel copolymers were investigated...
Real time mechano-optical properties of two homologous segmented, thermoplastic polyurethanes (TPUs) obtained from the stoichiometric reactions of trans-1,4-cyclohexyl diisocyanate (CHDI) and poly(tetramethylene oxide)glycol (PTMO) were investigated. PTMO oligomers used had number average molecular weights 〈M n 〉 of 1020 and 2040g/mol, resulting in TPUs with urethane hard segment contents...
Two series of hyperbranched polymers (HP), polyurethanes and polyureas, with aromatic and aliphatic structures, are synthesized in one-pot method using commercially available monomers. The obtained HP samples were characterized by 1 H Nuclear Magnetic Resonance (NMR) spectroscopy, Gel Permeation Chromatography (GPC), Differential Scanning Calorimetry (DSC) and Thermal Gravimetric Analysis...
Since its discovery in 2001, copper catalyzed azide–alkyne ‘click’ chemistry has been extensively used in polymer chemistry to modify polymeric materials and create advanced polymer structures by efficient coupling reactions. Surprisingly, the contribution of this Huisgen cycloaddition reaction to industrially important commodity polymers, prepared by step-growth polymerization, was not existing until...
The synthesis of polyisobutylene (PIB) based thermoplastic polyurethanes (TPU) with enhanced mechanical properties have been accomplished using poly(tetramethylene oxide) (PTMO) as a compatibilizer. PIB TPUs with Shore 60–100A hardness were prepared by employing PIB diols (hydroxyallyl telechelic PIBs) for the soft segment and 4,4′-methylenebis(phenylisocyanate) (MDI) and 1,4-butanediol (BDO) for...
The effects of nano-size fillers on shape memory (SM) properties of polyurethane (PU) nanocomposites were evaluated. Organoclay, carbon nanofiber (CNF), silicon carbide (SiC), and carbon black (CB) were selected as the fillers in an attempt to reinforce the PU and to obtain significantly increased shape recovery stress. The shape memory PU was synthesized from diphenylmethane diisocyanate, 1,4-butanediol,...
Correlations between polyurethane foam formulation and foam aging are shown to simplify when sufficient data are available to eliminate casual relationships. The numerous factors that are purported to result in faster or slower foam aging are shown to primarily reflect how those factors influence polyurethane hard segment structure. Specifically, changes in formulation that results in better phase...
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