Poly E-caprolactone Diol Research Articles

Bisphenol A Diglycidyl Ether-Primary Amine Cooligomer-poly(ε-caprolactone) Networks: Synthesis and Characterization.

In this work, the preparation and systematic investigation of cross-linked polyurethane-epoxy (PU-EP) polymer systems are reported. The PU-EP polymers were prepared using a reaction of isocyanate (NCO)-terminated PU-prepolymer with diglycidyl ether of bisphenol A (DGEBA)-amine cooligomer. The oligomerization of DGEBA was carried out by adding furfurylamine (FA) or ethanolamine (EA), resulting in DGEBA-amine cooligomers. For the synthesis of NCO-terminated PU-prepolymer, poly(ε-caprolactone)diol (PCD) (Mn = 2 kg/mol) and 1,6-hexamethylene diisocyanate (HDI) were used. The cross-linking was achieved by adding DGEBA-amine cooligomer to PU-prepolymer, in which the obtained urethane bonds, due to the presence of free hydroxil groups in the activated DGEBA, served as netpoints. During cross-linking, ethanolamine provides an additional free hydroxyl group for the formation of a new urethane bond, while furfurylamine can serve as a thermoreversible coupling element (e.g., Diels-Alder adduct). The PU-EP networks were characterized using attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC), dynamical mechanical analysis (DMA) and scanning electron microscopy (SEM). The DMA curves of some PU-EPs (depending on the compositions and the synthetic method) revealed a plateau-like region above the melting temperature (Tm) of PCD, confirming the presence of a cross-linked structure. This property resulted in a shape memory (SM) behavior for these samples, which can be fine-tuned in the presence of furfurylamine through the formation of additional thermoreversible bonds (e.g., Diels-Alder adduct).

Novel Polyurethane Scaffolds Containing Sucrose Crosslinker for Dental Application.

In this paper, the synthesis, characterization, and properties of crosslinked poly(ε-caprolactone)-based polyurethanes as potential tissue replacement materials are reported. The polyurethane prepolymers were prepared from poly(ε-caprolactone)diol (PCD), polyethylene glycol (PEG)/polylactic acid diol (PLAD), and 1,6-hexamethylene diisocyanate (HDI). In these segmented polyurethanes, the role of PEG/PLAD was to tune the hydrophobic/hydrophilic character of the resulting polymer while sucrose served as a crosslinking agent. PLAD was synthesized by the polycondensation reaction of D,L-lactic acid and investigated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and nuclear magnetic resonance spectroscopy (NMR). The crosslinked polyurethane samples (SUPURs) obtained were characterized by attenuated total reflectance Fourier-transform infrared spectroscopy (AT-FT-IR), swelling, and mechanical (uniaxial tensile tests) experiments. The thermo and thermomechanical behavior were studied by differential scanning calorimetry (DSC) and dynamical mechanical analysis (DMA). The viability of dental pulp stem cells was investigated in the case of polyurethanes composed of fully biocompatible elements. In our studies, none of our polymers showed toxicity to stem cells (DPSCs).

New Segmented Poly(Thiourethane-Urethane)s Based on Poly(ε-Caprolactone)Diol Soft Segment: Synthesis and Characterization.

New segmented poly(thiourethane-urethane)s (SPTURs) were synthesized by the reaction of 1,1′-methanediylbis (4-isocyanatocyclohexane) (Desmodur W®, HMDI) and poly(ε-caprolactone)diol (PCL) and (methanediyldibenzene-4,1-diyl)dimethanethiol as nonconventional polymer chain extender. FTIR spectroscopy was used for the structural analysis of obtained polymers. The molecular weight distribution was examined by GPC chromatography. Based on the measured contact angles, free surface energy parameters were calculated. Thermal properties of polymers were examined by DSC and TGA, while viscoelastic properties were measured by DMTA. The tensile, adhesive and optical properties were also investigated for the obtained polymers. It was shown that SPTURs were transparent or partially transparent solids with high molar masses up to 84,300 Da. These polymers showed a good resistance to hydrolysis during incubation in Optylite® physiological saline over 8 weeks. Obtained polymers possessed a tensile strength of up to 43.26 MPa, hardness of up to 96.25/59.00 Sh A/D and adhesion to copper of 14.66 MPa. The surface properties of the obtained polymers show that all obtained SPTURs were hydrophilic (CAs for water between 64.07° and 73.12°) with calculated SFE up to 46.69 mN/m.

Development of semi-crystalline polyurethane with self-healing and body temperature-responsive shape memory properties

Recently, polyurethane (PU) with multifunctionality has attracted significant attention in biomedical applications. This study reports semi-crystalline PUs with both shape memory and self-healing effects, which are composed of poly(ε-caprolactone) diol (PCL), isophorone diisocyanate (IPDI), and 1, 4-butanediol (BDO). The hard segment content greatly influences the structure, morphology and properties, and the increasing hard segment content promotes the phase separation and reduces the crystallizability of the soft segments. Herein, a new self-healing morphology of the semi-crystalline SMPUs is observed, and the self-healing mechanism is ascribed to the diffusion of soft segments and the stability of the hard domains. The relationship between the self-healing efficiency and the stability of hard domains is also explored. Furthermore, the shape memory mechanism of IPDI-based PU is clarified. Based on the partial melting state of the soft segment crystals, the PUs feature relatively good shape memory properties, and the response temperature can be designed as body temperature (37 °C). As the hard segment content increases, the value of shape fixity increases, while that of shape recovery decreases, which is related to hydrogen bonding between polymer chains. Considering the excellent biocompatibility, the as-designed semi-crystalline SMPUs are expected to be used as smart biomaterials in biomedical devices.

Synthesis and properties of UV-curable polyester acrylate resins from biodegradable poly(l-lactide) and poly(ε-caprolactone)

Three kinds of bio-based polyester diols with different chain lengths, including polylactide diol (PLA-D), poly(ε-caprolactone) diol (PCL-D) and poly(ε-caprolactone-co-lactide) diol (PCLA-D), were synthesized by controlled ring-opening polymerization (ROP). Then UV-curable polyester acrylate resins (PLA-DA, PCL-DA and PCLA-DA) were synthesized by esterification modifying bio-polyols with methacrylic anhydride. Furthermore, the effects of chain length and polymer composition on the UV-curing and mechanical properties of polyester resins were investigated. The viscosity of both PLA-DA and PCL-DA increased sharply with the increase of molecular weight, and PCL can reduce the viscosity of PCLA-DA effectively. In the study of UV-curing kinetics, the increase of viscosity has a negative effect on the conversion and curing of double-bonds. The change trend of gel contents is basically consistent with the curing kinetics. The results of mechanical properties showed that the viscosity and double-bond conversion of the resins had a decisive influence on the mechanical properties of UV-cured materials. It was also found that with the increase of double-bond conversion and cross-linking density, the volume shrinkage of UV-cured materials increased significantly. The results of thermal analysis showed that the thermal stability of PCL-DA was better than that of PLA-DA, and the addition of PCL segments enhanced the thermal stability of PCLA-DA.

New Polyurethane Urea Thermoplastic Elastomers with Controlled Mechanical and Thermal Properties for Medical Applications

The method of synthesis of new polyurethane urea thermoplastic elastomers with controlled physical network density by varying the crystallization rate of the soft block and the structure of the interphase has been developed. Fine-tuning of morphology and mechanical properties allows to desighn adaptive materials with shape memory. By combination of calorimetric and X-ray diffraction methods, the influence of chemical nature of diaisocyanates and the ratio of two types of crystallizable blocks, polybutylene glycol adipate diol (PBA) and poly-ε-caprolactone diol (PCL), on the structure and termal behavior of the thermoplastic elastomers has been studied.

Enhancing the recrystallization ability of bio-based polylactide stereocomplex by in situ construction of multi-block branched conformation

To enhance the formation and regeneration ability and the toughness of stereocomplex polylactide (sc-PLA), a high molecular weight stereocomplex branched multi-block polylactide (sb-PCLDA) was synthesized from d-lactide, l-lactide and poly(e-caprolactone) diol (PCL). High molecular weight sc-PLA has attracted much attention in bioengineering because of its good mechanical and thermal properties, but its brittleness and the poor regeneration ability of the sc crystallites hindered the practical processability, that is, the mixed homochiral and sc crystallites would form in the sc-PLA products after the complete melting and recrystallization processing. The high molecular weight sc-PLA which is easy to form complete stereocomplex and suitable for melt processing needs further research. Herein, sb-PCLDA having PCL, PLLA and PDLA segments on one molecular chain has been synthesized by polymerization of l-lactied and d-lactide with PCL and in situ hydrolysis condensation with silane coupling agents. Differential scanning calorimetry and wide angle X-ray diffraction indicated that sb-PCLDA formed complete sc with high crystallinity and exhibited good sc reformulation ability after multiple melting, suggesting much improved processability. Meanwhile, the sb-PCLDA maintained good thermal properties and hydrolysis resistance. The polymer exhibited significant tensile toughness with an elongation at break of 185%. This facile method could simultaneously improve the mechanical property and recrystallization ability of sc-PLA.

Hydrolytic and enzymatic degradation studies of aliphatic 10-undecenoic acid-based polyesters

The hydrolytic and enzymatic degradations of aliphatic polyesters: poly (10,11-epoxyundecanoic acid) (PEAU) bearing hydroxyl groups along the main chain and poly (11-hydroxyundecanoate)diol (PHU), were studied and compared to that of commercial poly (ε-caprolactone)diol (PCL). Changes taking place after polyester degradation in sample weight, molecular weight (Mn), chemical constitution, thermal properties, crystallinity and morphology were monitored by size exclusion chromatography (SEC), 1H nuclear magnetic resonance (NMR) spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-Ray diffraction (XRD) and environmental scanning electron and atomic force microscopies (ESEM and AFM). A significant decrease of PEUA Mn in both hydrolytic and enzymatic degradation was detected versus PHU and PCL, and related to its hydrophilic character, by the presence of hydroxyl pendant groups, and the superior amorphous character. An accelerated degradation in acidic media, monitored by SEC and 1H NMR spectroscopy to study in detail all residual material of three polyesters, showed the complete degradation only in the case of PEUA and PCL.

P.3.a.004 - Abnormal visual scanning during reality evaluation and its relationship to magical ideation in schizophrenia

The hydrolytic and enzymatic degradations of aliphatic polyesters: poly (10,11-epoxyundecanoic acid) (PEAU) bearing hydroxyl groups along the main chain and poly (11-hydroxyundecanoate)diol (PHU), were studied and compared to that of commercial poly (ε-caprolactone)diol (PCL). Changes taking place after polyester degradation in sample weight, molecular weight (Mn), chemical constitution, thermal properties, crystallinity and morphology were monitored by size exclusion chromatography (SEC), 1H nuclear magnetic resonance (NMR) spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-Ray diffraction (XRD) and environmental scanning electron and atomic force microscopies (ESEM and AFM). A significant decrease of PEUA Mn in both hydrolytic and enzymatic degradation was detected versus PHU and PCL, and related to its hydrophilic character, by the presence of hydroxyl pendant groups, and the superior amorphous character. An accelerated degradation in acidic media, monitored by SEC and 1H NMR spectroscopy to study in detail all residual material of three polyesters, showed the complete degradation only in the case of PEUA and PCL.

Synthesis, characterization and effects of arm number on properties of amphiphilic polyurethanes as drug delivery carriers

ABSTRACTAmphiphilic polyurethanes based on methoxy poly(ethylene glycol) (mPEG) and poly(ϵ-caprolactone) diol (PCL) with different arm numbers such as two, three and four were successfully synthesized. Their structures were confirmed by Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (1H NMR) and gel permeation chromatography (GPC). The effects of arm number on properties of amphiphilic polyurethanes were studied. Pyrene fluorescence probe technique and dynamic light scattering (DLS) analyses showed that the CMC value and the micellar size of the resultant amphiphilic polyurethanes decreased and the micellar stability against dilution enhanced with increasing the arm number of polyurethane. Using indometacin (IMC) as a model drug, the results indicated that the drug loading capacity and in vitro drug sustained release effect of polyurethane with four arms were better than those of polyurethanes with two and three arms.

Microwave radiation in the synthesis of urethane prepolymers

This paper describes the use of microwave radiation in the synthesis of urethane prepolymers in bulk (without solvent). The prepolymers were synthesized using 1,6-hexamethylene diisocyanate (HDI) and poly (ε-caprolactone) diol (PCL) at a molar ratio of 4:1. The reaction was carried out without a catalyst in the reactor with a conventional heating system (oil bath) or in the microwave reactor (MW Reactor NOVA 09) at temperatures of 60, 80 and 100°C. The progress of the reaction was monitored based on the degree of HDI and PCL conversion, as assessed by acidimetric titration of non-bonded isocyanate groups (0–120min). The chemical structure of the resulting products was determined via Fourier Transform Infrared Spectroscopy. Size exclusion chromatography (GPC) was applied to determine the molecular weight distribution of products at different time points of prepolymer synthesis. The obtained results indicate that the use of microwave radiation as a heat source during prepolymer synthesis accelerates the reaction in the temperature range from 60 to 80°C. This finding allows a significant reduction in energy required for heating the reaction mixture. The acceleration of prepolymer synthesis by the application of microwave radiation as a heat source also allows for the elimination of catalysts from the system. The aforementioned catalysts are necessary to perform the prepolymer synthesis with the use of aliphatic diisocyanates and polyols, particularly at temperatures below 100°C. In the case of prepolymers that are further used in the synthesis of biomedical polyurethanes, the catalyst elimination is especially advantageous as the presence of residual catalyst may significantly influence the final material’s biocompatibility and disturb host cell viability.

Biomimetic polyurethane – Based fibrous scaffolds

The design of biomimetic scaffolds that reproduce the biochemical, mechanical and structural functions of the ECM is a fundamental requirement to develop functional substrate for tissue engineering. To this aim, materials which combine the easy processability and mechanical properties of synthetic polymers with the biochemical cues provided by natural materials, develop positive interaction with cells, enabling tissue regrowth in vivo. In this work, a polyester urethane (NS-BC2000) was synthesised using poly (ε-caprolactone) diol (PCL) as macrodiol, 1,4-diisocyanatobutane (BDI) as diisocyanate and N-Boc serinol as chain extender. After Boc cleavage (S-BC2000) to expose free amino groups, a S-BC2000/PEO (80/20wt./wt.) solution was successfully electrospun fabricating aligned nanofibres with a fibre size of 2.8±0.6µm.The aligned nanofibres were then functionalised with IKVAV peptide that was covalently bound exploiting the presence of free amino groups on S-BC2000 chains.

Relationship between reagents molar ratio and dispersion stability and film properties of waterborne polyurethanes

Environmentally-friendly waterborne polyurethanes showing a broad range of properties have been synthesized by the prepolymer method. A macrodiol based on poly(ϵ-caprolactone) diol (PCL) was used as soft segment (SS) and isophorone diisocyanate (IPDI), 2-bis(hydroxymethyl) propionic acid (DMPA) and 1,4-butanediol (BD) as hard segment (HS). The IPDI/(PCL + DMPA) and PCL/DMPA molar ratio were varied in order to determine the influence of these variables in particle size and stability of dispersions and also in final properties of polymer films. Particle size of the obtained dispersions, determined by means of dynamic light scattering, showed a narrow distribution with small particle diameters. Isocyanate content increase leads to bigger particles due to urethane linkages which restrict chain mobility, whereas DMPA content increase promotes small particles due to higher density of ionic groups. The stable dispersions have been used for films preparation, which have been characterized from the view point of their physicochemical, thermal and mechanical properties, as well as morphology. The increase of IPDI/(PCL + DMPA) molar ratio leads to higher yield stress, stress at break and modulus, maintaining high elongation at break values. Nevertheless, the increase of DMPA content promotes less crystalline soft domains achieving soft segment strain induced crystallization under stress and thus, obtaining higher stress at break and improving elongation at break. Films surface hydrophilicity is predominantly affected by IPDI/(PCL + DMPA) molar ratio, whereas water diffusion depends on DMPA content.

Synthesis of biodegradable polycaprolactone/polyurethane by curing with H2O

To prepare a pre-polymer in this study, the following materials were used: 4,4′-diphenylmethane diisocyanate, poly(e-caprolactone) diol (PCL), and polytetramethylene ether glycol. The pre-polymer was then cured using H2O to form a new type of polyurethane (PU), PCL/H2O-PU. Fourier transform infrared analysis confirmed the successful synthesis of PCL/H2O-PU. Results from thermal gravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis showed that the thermal resistance and glass transition temperature of PCL/H2O-PU increased with the H2O and the hard segment content. Stress–strain curves for the PCL/H2O-PU specimens showed that with increasing H2O content, the tensile strength and Young’s modulus increased, but the elongation at break decreased. WAXD patterns indicated that with a higher H2O content, the polymer chains were in a more ordered arrangement, although the morphology was still amorphous. The degree of swelling in an aqueous ethanol solution and the hydrolytic degradation rate increased with the PCL content. Scanning electron microscopic images showed that during the degradation period, the original wrinkled surface of PCL/H2O-PU became smooth, and then cracks were formed. The cracks became more severe when the degradation was at a higher temperature.

Synthesis of MDI and PCL-diol-based polyurethanes containing [2] and [3]rotaxanes and their properties

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 poly(ε-caprolactone)diol (PCL) were used as an isocyanate, chain expander, and soft segment, respectively. A polyurethane without any rotaxane structures (PU0) were also prepared as a reference polymer. The existence of the rotaxanes in the polyurethanes was confirmed by 1H NMR spectroscopy and TGA measurement. ATR-FT-IR spectral measurement revealed that the rotaxanes disturb the formation of hydrogen bonding between the polyurethane chains. From the DSC result, the rotaxanes retard the recrystallization of the PCL unit whereas no influence on the glass transition temperatures of the polyurethanes was observed. The retarding effect appeared remarkably with PU1. These thermal behaviors of the polyurethanes were also supported by viscoelastic measurement. In tensile test, the tensile strength and break of strain of PU1 were larger than those of PU2.

Enzymatic degradation and radiopaque attenuation of iodinated poly(ester-urethane)s with inherent radiopacity

Biodegradable radiopaque iodinated polyurethanes (I-PUs) based on poly(e-caprolactone) diol (PCL) as soft segment have been synthesized using 4,4′-isopropylidene-(2,6-diiodophenol) (IBPA) as chain extender. In order to elucidate the effect of iodinated chain extender on degradation properties of I-PUs, a control polyurethane with bisphenol A as chain extender was also synthesized. The enzymatic degradation study of these I-PUs was carried out using phosphate-buffered solution (pH 7.4) at 37 °C. The mass loss, surface morphology, iodine content, radiopacity, hydrophilicity and thermal properties of the samples during degradation were characterized with scanning electron microscopy (SEM), energy-dispersive X-ray detector (EDX), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and static contact angle. Results of enzymatic degradation during 3 months indicated that the incorporation of iodinated chain extender greatly hindered the in vitro degradation of I-PUs compared with the control PU-C sample. The reason for the retarded degradation was attributed to the bulky iodine atoms on IBPA chain extender with steric hindrance, which decreased the surface hydrophilicity of I-PUs and slowed water/lipase diffusion rate. Moreover, the radiopacity of I-PUs does not sharply attenuate after long-time degradation, which is useful for interventional biomedical applications.

Synthesis and characterization of biodegradable acrylated polyurethane based on poly(ε-caprolactone) and 1,6-hexamethylene diisocyanate

A series of biodegradable acrylic terminated polyurethanes (APUs) based on poly(ε-caprolactone) diol (PCL), aliphatic 1,6-hexamethylene diisocyanate (HDI) and hydroxyethyl methyl acrylate (HEMA) was synthesized as potential materials for hard tissue biomedical applications. PCLs with low molecular weights of 1000 and 2000g/mol were employed to provide different amounts of end capped urethane acrylate in APUs. To control crosslink density, a mixture of two different reactive diluents including mono-functional HEMA and bi-functional ethylene glycol dimethacrylate (EGDMA) with different weight ratios was incorporated into the APUs, called here PUAs. Morphological characteristics and mechanical properties were investigated using X-ray diffraction (XRD), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). DMA results indicated some degree of microphase separation between hard and soft segments; however, the microphase separation is more prominent for PUAs with higher molecular weight PCL. It was also found that the degree of crosslinking dominated greatly the formation of crystalline structure. PUAs with low crosslink density exhibited crystalline microstructure. The results also indicated that the mechanical properties of PUAs were governed considerably by crystalline microstructure, and hard segment content. All PUAs demonstrated hydrophobic behavior and were able to be degraded hydrolytically. The degradation process was closely related to the microstructure and surface tension of PUAs.

Polyurethane elastomers-based modified castor oil and poly(ε-caprolactone) for surface-coating applications

Polyurethanes (Pus) were synthesized from castor oil and modified through transesterification by pentaerythritol, poly(ε-caprolactone)diol (PCL), and isophorone diisocyanate to form PU coatings. The ratio of NCO/OH groups used was 1:1. The effect of varying the PCL content on the physical properties of wood panel PU coatings was determined. The PU coatings were characterized using Fourier transform infrared spectroscopic analysis, and the physicochemical properties, such as tensile strength, elongation at the break, shore A hardness, and the results of a lap shear test, were reported. Thermal properties of the PU coatings were evaluated using differential scanning calorimetry and thermogravimetric analysis. In vitro PU degradation was related to the hard segment structure and polymer hydrophilicity.

Effect of the diisocyanate structure and the molecular weight of diols on bio‐based polyurethanes

AbstractBio‐based polyurethanes (PU) containing poly(ε‐caprolactone) diol (PCL) and hydroxyl telechelic natural rubber (HTNR) were synthesized. The effect of the diisocyanate structure and the molecular weights of diols on the mechanical properties of PU were investigated. Three different molecular structures of diisocyanate were employed: an aliphatic diisocyanate (hexamethylene diisocyanate, HDI), an aromatic diisocyanate (toluene‐2,4‐diisocyanate, TDI) and a cycloalkane diisocyanate (isophorone diisocyanate, IPDI). Two molecular weights of each diol were selected. When HDI was employed, a crystalline PU was generated while asymmetrical structures of TDI and IPDI provided an amorphous PU. The presence of crystalline domains was responsible of a change in tensile behavior and physical properties. PU containing TDI and IPDI showed a rubber‐like behavior: low Young's modulus and high elongation at break. The crystalline domains in PU containing HDI acted as physical crosslinks, enhancing the Young's modulus and reducing the elongation at break, and they are responsible of the plastic yielding. The crystallinity increased the tear strength, the hardness and the thermal stability of PU. There was no significant difference between the TDI and IPDI on the mechanical properties and the physical characteristics. Higher molecular weight of PCL diol changed tensile behavior from the rubber‐like materials to the plastic yielding. Thermal and dynamic mechanical properties were determined by using DSC, TGA and DMTA. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Synthesis and properties of biodegradable polycaprolactone/polyurethanes by using 2,6-pyridinedimethanol as a chain extender

In this study, 4,4′-diphenylmethane diisocyanate (MDI) and poly(ε-caprolactone) diol (PCL) were used to prepare a prepolymer and then 2,6-pyridinedimethanol (2,6-PDM) was used as a chain extender to prepare a new polyurethane, PCL/PDM-PUs. FT-IR analysis confirms the successful synthesis of PCL/PDM-PUs. TGA, DSC and DMA results show that thermal resistance, Tg and dynamic Tg of the compound increase with increasing 2,6-PDM content. Stress–strain curves for the PCL/PDM-PUs show that the tensile strength and elongation at break raise with increasing 2,6-PDM content, whereas Young's modulus decreases with increasing 2,6-PDM content. XRD patterns indicate that polymer chains of the amorphous compound can be more orderly arranged by the presence of higher 2,6-PDM content, although the morphology is still amorphous. Moreover, the swelling degree in aqueous ethanol solution and the hydrolytic degradation rate increase with increasing PCL content. SEM images show that during the degradation period, the original wrinkled surface of PCL/PDM-PUs became smoother first, and then cracks were formed later. The cracks became more severe when subjected to higher temperature.