Poly E-caprolactone Diol Research Articles

Study on the Synthesis and Properties of Biodegradable Waterborne Polyurethane

Taking L-Lysine Diisocyanate (LDI) as hard segments, poly-ε-caprolactone diol (PCL) as soft segments, a kind of nontoxic and biodegradable waterborne polyurethanes were synthesized using two-step polymerization. And then the effects of isocyanate/macroglycol molar ratio(NCO/OH, R value), the 1,4-butylene glycol (BDO) content and prepolymerization temperature on the properties of waterborne polyurethanes were investigated. The experimental results showed that when R value is 1.5, the BDO content used is 4% and the reaction temperature is 80°C, the products prepared were best in application. The mechanical property tests showed that it has good mechanical properties, tensile strength is up to 46.5MPa and the loss amounts of the hydrolytic degradation after 80 days is 42%. The waterborne polyurethanes prepared have excellent biodegradability, which can be widely used as a biological medical material.

Electrospinning and biocompatibility evaluation of biodegradable polyurethanes based on L‐lysine diisocyanate and L‐lysine chain extender

A series of biodegradable polyurethanes (PUs) were synthesized using poly(ε-caprolactone) diol (PCL) to react with L-lysine ethyl ester diisocyanate (LDI) chain extend with L-lysine ethyl ester (LEE) in solution of DMF. The structure was characterized by gel permeation chromatography, ¹H-NMR, Fourier transform infrared, and DSC analyses. Mechanical property testing showed that their tensile strength rose with increasing the hard segment content with a maximum tensile strength of 34.43 ± 1.73 MPa. The average mass loss for the hydrolytic degradation was only about 13 % in 56 days while this value for the enzymatic degradation was around 95 % in 30 days. The morphological and biomechanical characters of the tubular scaffolds electrospun from the as-prepared PUs were also examined. As the solution concentration was varied from 10 to 18% (w/v), the fiber diameter was progressively increased, and the scaffold tensile strength was enhanced from 2.82 ± 0.16 MPa to 7.07 ± 0.44 MPa, the suture retention strength from 2.48 ± 0.33 to 8.38 ± 0.35 N, and the burst pressure strength from 72 ± 2 to 172 ± 2 kPa, all higher than those of native blood vessels. At the same time, the L-929 mouse fibroblasts (L-929) and human umbilical vein endothelial cells were used in cytotoxicity and cell-adhesion evaluations toward the electrospun scaffolds. The level of toxicity is less than level 1, and cells were found to attach well to and remain viable on the scaffolds.

Isothermal Crystallization Behavior of Poly(ϵ-Caprolactone) Diol/Functionalized-Multiwalled Carbon Nanotube Composites

Isothermal crystallization behavior of poly (ϵ-caprolactone) diol (PCL)/functionalized-multiwalled carbon nanotube (f-MWNTs) composites at three different temperatures (30°, 35°, 40°C), with varying molecular weights (MW) of PCL (2000, 4000, 8000 g/mol) and loadings of f-MWNTs (0, 0.1, 1.0, 5.0 wt.%), was studied by differential scanning calorimetry (DSC), polarized optical microscopy (POM), and X-ray diffraction methods. DSC isotherm showed that introduction of f-MWNTs into PCL induced a heterogeneous nucleation in the crystallization growth process, thereby lowering the activation energy for the crystallization process appreciably. POM showed the spherulite structure of neat PCL, whereas the composites showed the spherulite structure containing f-MWNTs at the center, indicating nucleating action of f-MWNTs in the crystallization process. The spherulite size decreased but its number increased with increasing weight proportion of f-MWNTs and MW of PCL.

Effect of Multiwalled Carbon Nanotubes on Crystallization Behavior of Poly(e-caprolactone)diol

Multiwalled carbon nanotubes (MWNTs) were found to be well dispersed in poly(ε-caprolactone)diol (PCL) matrix after grafting to the surface of MWNTs by grafting to approach. Afterward, the effect of MWNTs on nonisothermal crystallization of PCL was investigated by differential scanning calorimetry (DSC), X-ray diffraction spectroscopy, and polarized optical microscopy (POM). From the DSC observation, the onset and peak crystallization temperatures of the composites were found to be always higher than those for neat PCL, indicating high nucleation ability of MWNTs in PCL. However, the crystallization rate, characterized by inversed half-crystallization time of the composite was lower than that of the neat PCL. The experimental data were analyzed using modified Avrami equation, and the activation energy for crystallization for PCL was found to reduce in the presence of MWNTs. POM showed a direct evidence for nucleating action of MWNTs in the crystallization process.

Application of shape memory polyurethane in orthodontic

A shape memory polymer wire for orthodontic application was prepared by melt-spinning of polyurethane block copolymer (PU) which was synthesized in a two-step process from a reaction of 4,4'-methylene bis(phenylisocyanate), poly(ε-caprolactone)diol (PCL), and 1,4-butanediol. An orthodontic test using the PU wire was carried out in an orthodontic model with a metal bracket. High shape recovery force of 70 gf for PU wire at 40 wt% hard segment content could be preserved for even 1 month after a shape recovery force test at a constant temperature of 50°C. The shape recovery force decreased exponentially during the initial 2 h, but reached an equilibrium shape recovery force of 50 gf after about 20 days. It was found that this shape recovery force was sufficient to correct misaligned teeth in the orthodontic test. The shape memory PU wire possesses strong potential as a novel orthodontic appliance with esthetically appealing appearance.

Influence of Catalyst Type on Biocompatibility of Polyurethanes

Segmented polyurethanes (PUR) based on poly(ε-caprolactone)diol (PCL) as soft segments and cycloaliphatic diisocyanate were obtained. Two different types of catalysts were used for synthesis: dibutyltin dilaurate (DBTDL) and iron (III) acetylacetonate Fe(acac)3. Structure, thermal analysis, water absorption of obtained polyurethanes were studied. Polyurethanes catalyzed by Fe(acac)3 have lower glass transition temperature (Tg2) and melting temperature (Tm2) of hard domains in comparison with polyurethanes synthesized with DBTDL. Amount of absorbed water is in the range of 1,0-2,0% and is higher for PUR catalyzed by DBTDL. SEM observations show that type of catalyst used in synthesis affect structure of polyurethanes. Biological test XTT was done in order to determine influence of various metallic compounds used as catalyst on viability of human bone cell culture. The XTT results indicate no influence on viability of human osteoblasts cultured on the obtained PUR.

ポリウレタン ＩＩ ポリウレタン弾性糸に関する研究 （第２報） ハードセグメントの一次構造とポリウレタン弾性糸の弾性機能

Various types of chain extenders were used as hard-segment of the polyurethane yarn made of poly ε-caprolactone diol (PCL) as a soft-segment, and their physical and elastic properties were compared. It was found that ethylene diamine as the chain extender is siutable, because of it′s good balanced physical and elastic properties. And the introduction of urethane bond made of glycol and aromatic group into hard-segment is recommended to improve tensile elongation and wet heat set of the polyurethane yarn.

ポリウレタン ＩＩ ポリウレタン弾性糸に関する研究 （第１報） ソフトセグメントの一次構造とポリウレタン弾性糸の弾性機能

The relationships between soft-segments and the elastic properties of polyurethane yarns were studied. Poly e-caprolactone diol(PCL), e-caprolactone(CL)-ethyleneoxide(EO) copolymer diol, PCL-polypropylene glycol (PPG) block copolymer diol, PCL/PPG blend and polytetramethylene glycol (PTG) were used as soft-segments. The effects of molecular weight and molecular weight distribution of diols, and also the effects of chain length of soft-segments on the elastic properties of polyurethane yarns were examined. It was found that the permanent set of polyurethane yarn was related to the chain length of soft-segment and the melting point of diol.

Properties of some cast polyurethane rubbers prepared from poly‐ε‐caprolactone polyols and diisocyanates

AbstractPolyurethanes were prepared by a one‐step method from poly‐ε‐caprolactone (PCL) diols, diisocyanates, and a triol crosslinking agent (either PCL triol or trimethylolpropane). The influence of composition on mechanical properties was examined. In some formulations the elastomeric properties were lost by crystallization of the PCL segments. The occurrence and rate of crystallization were influenced by the composition and factors such as hydrolytic degradation and oil swelling. In one series of polymers the susceptibility to crystallization could be predicted from the composition. These materials showed melting and glass transitions when examined by differential scanning calorimetry and thermomechanical analysis. The molecular weight of the PCL diol had a greater influence on the glass transition temperature than the diol concentration.