Poly Hexamethylene Carbonate Diol Research Articles

Colorless, transparent, and shape memory polyurethane networks with high strength and recyclability

AbstractThe traditional thermoset polyurethanes (PUs) can be recycled through the dynamic carbamate bonds under specific conditions. However, there is limited research on the structural evolution and property changes of these PUs before and after recycling. Herein, we designed and fabricated a thermoset polyurethane network (PCU) using polyhexamethylene carbonate diol (PHMC‐diol) as soft segments, and isophorone diisocyanate (IPDI) and glycerol (GLY) as hard segments. Through careful formulation design, the PCU demonstrated colorless transparency (with up to 86% transmission), shape memory properties, and reprocessing capabilities, all achieved without introducing other dynamic covalent bonds. Furthermore, the PCU exhibited excellent mechanical properties, boasting a tensile strength of 59.2 ± 3.7 MPa and the elongation at break of 674.8 ± 37.3%. Of particular interest, the PCU samples displayed solid‐state plasticity and impressive shape memory performance, with shape fixity and recovery ratios exceeding 90%. Leveraging the combination of solid‐state plasticity and shape memory, the PCU samples demonstrated the ability to achieve arbitrary shape manipulations. Upon recycling, it was observed that the cross‐linking density of the PCU samples decreased, resulting in the formation of byproducts and subsequently leading to a reduction in tensile strength. Nonetheless, the PCU samples prepared in this study exhibit potential as thermadapt shape memory and recyclable materials.

Thermoplastic polyurethane-based polycarbonate diol hot melt adhesives: The effect of hard-soft segment ratio on adhesion properties

Polycarbonate-based thermoplastic polyurethane elastomers (PCD-TPUs) were synthesized from polyhexamethylene carbonate diol, 4,4-diphenylmethane diisocyanate and 1,4 butanediol, intended for adhesive applications. The chemical structure, thermal transition temperature, phase separation morphology, mechanical properties, and adhesion properties were studied to elucidate the structure-properties relationship of PCD-TPUs as a function of hard segment content. The phase separation behavior was described as a shift of the glass transition temperature and the dimension size of the hard domain. It was found that the higher hard segment fraction led to a lower degree of phase separation as well as a reduction in tensile strength and elongation at break. The hydrogen bonding characteristic of PCD-TPUs was investigated by FTIR. The presence of free hydrogen bonded PCD-TPUs benefits the higher peel strength since it promotes hydrogen bonding interaction with the substrate. The peel strength was obtained from PCD-TPUs/stainless steel joint. The adhesion properties of the adhesive system were strongly influenced by the soft segment. These results can establish the possibility of designing new formulations for hot melt adhesive.

Synthesis and characterization of X-ray opaque polycarbonate urethane: Effect of a dihalogenated chain extender on radiopacity and hemocompatibility.

An inherently radiopaque poly(carbonate urethane) containing fluorine and iodine atoms in the polymer chain was synthesized and characterized. Radiopaque polyurethane was synthesized from 1,6-diisocyanatohexane (HDI), poly (hexamethylene carbonate)diol (PHCD) and a newly synthesized chain extender having fluorine and iodine in the molecule, namely, 4,4'-(1,1,1,3,3,3-hexafluoropropane-2,2-diyl)bis(2,6-diiodophenol) (IBAF). IBAF monomer imparted radiopacity and improved the hemocompatibility of the resultant polymer. For comparative evaluation, polyurethanes (PU) were synthesized by reacting monomers HDI and PHCD without any chain extender and also by reacting HDI and PHCD along with noniodinated, but fluorine containing, version of the above chain extender, namely, 4,4'-(Hexafluoroisopropylidene) diphenol (BAF). Chain extended PUs showed improved mechanical and thermal properties, and hemocompatibility compared to the nonchain extended PU. Radiopacity measurements by fluoroscopy showed that IBAF incorporated PU of 200 µm thickness had radiopacity equivalent to that of 25% barium sulfate filled noniodinated PU of same thickness and to that of 0.6-mm thick aluminum wedge. In vivo imaging using a rabbit cadaver model showed clearly distinguishable image of IBAF incorporated PU sample. All the PU materials were noncytotoxic to L929 mouse fibroblast cells. Preliminary results obtained from blood-material interaction studies showed that incorporation of fluorinated chain extenders in the PUs resulted in significant reduction in the adhesion of white blood cells onto the PU material surface and also resulted in prolonged partial thromboplastin time. Results suggest that incorporation of fluorine and iodine containing chain extenders would lead to the development PU with improved hemocompatibility and radiopacity.

New thermoplastic poly(thiourethane-urethane) elastomers based on hexane-1,6-diyl diisocyanate (HDI)

Two series of new thermoplastic poly(thiourethane-urethane) elastomers (EPTURs), with different hard-segment content (40–60 wt%), were synthesized by a one-step melt polymerization from poly(oxytetramethylene) diol (PTMO) of $$ \overline{M}_{\text{n}} $$ = 1,000 g mol−1 or poly(hexamethylene carbonate) diol (PHCD) of $$ \overline{M}_{\text{n}} $$ = 860 g mol−1 as a soft segment, hexane-1,6-diyl diisocyanate and (methylenedi-1,4-phenylene)dimethanethiol as a chain extender at the NCO/(OH + SH) molar ratio of 1. The structures of all the EPTURs were examined by Fourier transform infrared spectroscopy (FTIR), atomic force microscopy and X-ray diffraction analysis. Their thermal behavior was investigated by means of differential scanning calorimetry and thermogravimetric analysis (TG). For the chosen polymers the gaseous products evolved during the decomposition process were analyzed by TG-FTIR. Moreover, physicochemical, adhesive and tensile properties as well as Shore A/D hardness were determined. The resulting high-molecular-mass EPTURs were stable up to 254–262 °C, as measured by the temperature of 1 % mass loss. They decomposed in three or four stages. The main decomposition products were carbonyl sulfide, isocyanate, carbon dioxide, aromatic hydrocarbons as well as aliphatic ethers and aldehydes (in PTMO series) and alcohols (in PHCD series). All the polymers showed partially crystalline structures, associated with crystallization of thiourethane hard segments. Their melting temperatures were in the range of 184–186 °C. The PTMO series EPTURs exhibited better low-temperature properties (glass-transition temperature in the range of −64 to −44 vs. −26 to −22 °C), but poorer tensile strengths (20–28 vs. 37–43 MPa). These EPTURs showed improved adhesive properties in comparison with their polyurethane analogs.

The synthesis and characterization of new thermoplastic poly(thiourethane‐urethane)s

AbstractNew thermoplastic segmented poly(thiourethane‐urethane)s (SPTUUs) were prepared by a one‐step melt polymerization from 20 to 80 mol % poly(tetramethylene oxide) of $\overline M _{\rm n}$ = 1000 or poly(hexamethylene carbonate) diol (PHCD) of $\overline M _{\rm n}$ = 860 as soft segments, hexamethylene diisocyanate (HDI) and bis[4‐(mercaptomethyl)phenyl]methanone (BMMPM) as a new dithiol chain extender at the NCO/(OH + SH) molar ratio of 1 in the presence of dibutyltin dilaurate as a catalyst. The structures of the SPTUUs were examined by FTIR, X‐ray diffraction analysis, and scanning electron microscopy. The SPTUUs were also characterized by physicochemical, thermal, and tensile properties as well as Shore A/D hardness. The SPTUUs with the PHCD soft segments showed better tensile properties than those with the PTMO soft segments. A nonsegmented polythiourethane based on BMMPM and HDI is also described. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1770–1782, 2008

Modified polycarbonate urethane: Synthesis, properties and biological investigation in vitro

A new polycarbonate urethane (PCU-I) was synthesized from aliphatic monomers, i.e. polyhexamethylene carbonate diol and 4,4'-methylene-bis cyclohexane diisocyanate, a mixture of low molecular diols, and castor oil (containing mainly the triglyceride of 12-hydroxyoleic acid). The second synthesized polymer (PCU-II) did not contain castor oil. Both PCUs had good tensile strength, i.e. 32.5 and 27.8 MPa for PCU-I and PCU-II, respectively. Modification by castor oil led to a decrease in glass transition temperature (T(g) = -14 degrees C for PCU-I and -6 degrees C for PCU-II) and an increase in the softening temperature (135 and 125 degrees C for PCU-I and PCU-II, respectively). Partial crosslinking of PCU-I increased the storage modulus of elasticity and provided better resistance to sterilization by ETO and gamma radiation. Both PCUs displayed good stability when subjected to sterilization by hydrogen peroxide plasma. Neither PCU caused cytotoxic effect in mouse fibroblasts (3T3 Balb C). They also had no toxic effects on the morphotic components and did not influence changes in the hematologic parameters or plasmatic coagulation system of human blood.

Mixed macrodiol-based siloxane polyurethanes: Effect of the comacrodiol structure on properties and morphology

Two series of polyurethanes were prepared to investigate the effect of comacrodiol structure on properties and morphology of polyurethanes based on the siloxane macrodiol, α,ω-bis(6-hydroxyethoxypropyl) polydimethylsiloxane (PDMS). All polyurethanes contained a 40 wt % hard segment derived from 4,4′-methylenediphenyl diisocyanate (MDI) and 1,4-butanediol (BDO), and were prepared by a two-step, uncatalyzed bulk polymerization. The soft segments were based on an 80/20 mixture of PDMS (MW 967) and a comacrodiol (MW 700), selected from a series of polyethers and polycarbonates. The polyether series included poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO), poly(tetramethylene oxide) (PTMO), poly(hexamethylene oxide), and poly(decamethylene oxide) (PDMO), whereas the polycarbonate series included poly (hexamethylene carbonate) diol (PHCD), poly [bis(4-hydroxybutyl)-tetramethyldisiloxy carbonate] diol (PSCD), and poly [hexamethylene-co-bis(4-hydroxybutyl)-tetramethyldisiloxy carbonate] diol (COPD). Polyurethanes were characterized by size exclusion chromatography, tensile testing, differential scanning calorimetry (DSC), and dynamic mechanical thermal analysis (DMTA). The results clearly demonstrated that the structure of the comacrodiol influenced the properties and morphology of siloxane-based polyurethanes. All comacrodiols, except PEO, improved the UTS of the polyurethane; PHMO and PTMO were the best polyether comacrodiols, while PSCD was the best polycarbonate comacrodiol. Incorporation of the comacrodiol made polyurethanes more elastomeric with low modulus, but the effect was less significant with polycarbonate comacrodiols. DSC and DMTA results strongly supported that the major morphological change associated with incorporation of a comacrodiol was the significant increase in the interfacial regions, largely through the compatibilization with the hard segment. The extent of compatibilization varied with the comacrodiol structure; hydrophilic polyethers such as PEO were the most compatible, and consequently, had poor mechanical strength. Among the polyethers, PHMO was the best, having an appropriate level of compatibility with the hard segment for substantial improvement in mechanical properties. Siloxy carbonate comacrodiol PSCD was the best among the polycarbonates. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1071–1082, 2000

Study on relationship between mechanical properties and particle size distribution for polyhexamethylene carbonate diol toughened epoxy resin

The relationship between the mechanical properties and morphology of polyhexamethylene carbonate diol (PHMCD) toughened epoxy resin was investigated. The parameters describing the morphology (e.g., average diameter of particles and volume fraction of dispersed phase, etc.) were determined through SEM observation. It was observed that the particle size distribution changes from a unimodal distribution to a bimodal one and then tounimodal again with an increase in curing temperature. When it was cured at 120°C, an epoxy resin with a bimodal distribution of rubber particle size was obtained. The mechanical properties, especially the impacting strength, of the resin are the best because of the synergistic effect of the PHMCD particles. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 569–575, 1998

Study on relationship between mechanical properties and particle size distribution for polyhexamethylene carbonate diol toughened epoxy resin

The relationship between the mechanical properties and morphology of polyhexamethylene carbonate diol (PHMCD) toughened epoxy resin was investigated. The parameters describing the morphology (e.g., average diameter of particles and volume fraction of dispersed phase, etc.) were determined through SEM observation. It was observed that the particle size distribution changes from a unimodal distribution to a bimodal one and then tounimodal again with an increase in curing temperature. When it was cured at 120°C, an epoxy resin with a bimodal distribution of rubber particle size was obtained. The mechanical properties, especially the impacting strength, of the resin are the best because of the synergistic effect of the PHMCD particles. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 569–575, 1998

Cure Kinetics of Epoxy Resin System Toughened by Polyhexamethylene Carbonate Diol

Cure Kinetics of Epoxy Resin System Toughened by Polyhexamethylene Carbonate Diol

Synthesis and physical properties of H12MDI-based polyurethane resins

This paper described the synthesis of four types of polyurethanes by using diisocyanato dicyclohexylmethane (H12MDI) as the hard segment and poly hexamethylene carbonate diol, polybutylene adipate diol, poly(hexamethylene diol/neopentyl glycol)-based copolyester diol, or poly hexamethylene diol/hexamethylene carbonate)-based copolyester/carbonate diol as the corresponding soft segment. The spectral analysis, thermal studies (differential scanning calorimetry and dynamic mechanical analysis), tensile strength-elongation relationship, and water vapor permeability of these samples were investigated. The results of these studies showed that the phase separation extent of the four types of polyurethanes displayed the following order: ESBA (polybutylene adipate-based polyurethane) > ECHH (co-polyester / carbonate-based polyurethane) > ESHN (copolyester diol-based polyurethane) > CAHC (polyhexamethylene carbonate-based polyurethane). The water vapor permeability of the cast films increased with the increase of the phase separation extent, in which the polyester-based polyurethane (sample ESBA) displayed the highest water vapor permeability. In terms of tensile strength-elongation property, the polycarbonate diol based polyurethane displayed higher tensile strength but lower elongation than polyester-based polyurethanes.