Caprolactone Diol Research Articles

Preparation and Characterization of PHBV/PCL-Diol Blend Films.

Biodegradable thin films based on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly(caprolactone diol) (PCL-diol) blend were developed using the solution casting method. PHBV is biodegradable, biocompatible, and produced naturally by bacterial activity, but its use is restricted by high crystallinity and low resistance to thermal degradation with melting temperatures close to degradation thus narrowing the processing window. Solution casting was chosen as a cost-effective method reducing energy consumption and avoiding thermal degradation during processing. The increase in PCL-diol in blend composition (40-60 wt%) enhances the film-forming ability of PHBV and the wettability along with the decrease in the roughness of the resulting materials as revealed by contact angle measurements, scanning electron microscopy (SEM), and atomic force microscopy (AFM). Optimal composition in terms of filmogenity and surface structure has been achieved by the addition of PCL-diol in the amount of 60 wt%. FTIR confirmed the expected chemical structures with no evidence of chemical interactions between the two polymers.

Influence of carbon nanotube functionalization on the physical properties of PCL diol/chitosan blends

AbstractBACKGROUNDChitosan‐poly(ε)caprolactone diol (PCL) blends were studied for food packaging film applications. The mechanical and thermal properties of blend films can be regulated with different amounts of PCL and the addition of a nanofiller could reinforce specific domains in the blend to generate nanocomposites with desirable properties for food packaging. This is evidence of the selective insertion of functionalized carbon nanotubes in either PCL or chitosan domains, depending on the nature of chemical groups and the structure over the surface nanofiller.RESULTSMultiwalled carbon nanotubes (MWNTs) were functionalized with four different dendritic molecules and were tested as nanofillers to reinforce biodegradable films made from 70 to 30, 80 to 20, and 90 to 10 Chitosan‐PCL blends in an effort to explore their effects on the barrier and mechanical properties of the yielded nanocomposites. PCL was obtained by biocatalysis from ɛ‐caprolactone and diethylene glycol and then blended with commercial chitosan. Blends were prepared from a solution of chitosan in acetic acid (2% wt/wt), adding PCL diol in chloroform dropwise under stirring. The MWNTs were modified with several functional groups (tannic acid via no‐covalent functionalization, poly(citric acid), poly(urea‐urethane), and poly(amino‐amido) dendrimer). Nanocomposites were obtained by adding in situ 0.5 wt/wt functionalized MWNTs during the preparation of blends. The structural interactions, morphological, and mechanical features of MWNTs/Blend nanocomposites were studied by Fourier‐transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscope (SEM), field emission scanning electron microscopy (FE‐SEM), and strain–stress testing.CONCLUSIONSPreferential interactions between nanofiller and matrix strongly depend on the nature of the nanofiller and the amount of hydrogen bonding species. It was possible to reinforce a particular domain in the blend to generate nanocomposites with desirable/tunable properties by using complementary chemical groups onto MWNTs surface. © 2023 Society of Chemical Industry (SCI).

Characterization of Films Based on Cellulose Acetate/Poly(caprolactone diol) Intended for Active Packaging Prepared by Green Chemistry Principles

Biodegradable active packaging films based on a cellulose acetate and poly(caprolactone diol) blend with incorporated lemongrass oil were developed. Films were prepared using a novel bio-based plasticizer, glycerol tritartarate, synthesized using the principles of green chemistry. The influence of the plasticizer, as well as the essential oil amount, on the structural, surface, mechanical, and thermal properties of the blend was investigated. The plasticizer was shown to work as a compatibilizer for two polymers, according to the results of scanning electron microscopy and surface energy analysis. Blends with a greater amount of plasticizer possessed better mechanical properties but showed worse resistance to water. The antimicrobial property of the blend with lemongrass oil was found to be superior to that of the blend without essential oil. The incorporation of lemongrass oil into the polymer blend resulted in one more step longer thermal degradation process. The optimal film properties, biodegradability, cost-effective preparation method, and additional functions made these films suitable for the production of packaging for grapefruit.

Preparation of Novel partially Bio-Based Thermoplastic Polyurethane / Polyacrylonitrile Electrospun Fiber Mats

The partially bio-based thermoplastic polyurethane/polyacrylonitrile electrospun fiber mats at various weight ratio was fabricated via electrospinning technique. A partially bio-based thermoplastic polyurethane was prepared from caprolactone diol and partially bio-based diisocyanate at a mole ratio of 2.1:1. Ethylene glycol was used as a chain extender. Three major effects i.e. solution concentration, distance from tip to collector and applied voltage on morphology of the obtained electrospun fiber mats were systematically investigated using a scanning electron microscope. The design of experiment, namely, Taguchi method was also applied. The morphology of the prepared electrospun fiber mats revealed continuous and smooth fibers without the formation of beads. The fiber diameters of the thermoplastic bio-based polyurethane/polyacrylonitrile were in micron size ranging from 0.2 to 1.4 μm. Moreover, the results showed that with the decrease of concentration, the fiber diameter decreased where the changes of applied voltage and distance from tip to collector resulted in negligible changes in fiber diameter. The findings can be further applied as processing conditions to meet properties requirements for the high-performance separator application.

XPS and ToF-SIMS Characterization of New Biodegradable Poly(Peptide-Urethane-Urea) Block Copolymers.

New, linear, segmented poly(peptide-urethane-urea) (PPUU) block copolymers are synthesized and their surface compositions are characterized with angle dependent X-ray photoelectron spectroscopy (ADXPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). These new PPUU block copolymers contain three types of segments. The soft segment (SS) is poly(caprolactone diol) (PCL). The hard segment is lysine diisocyanate with a hydrazine chain extender. The oligopeptide segment (OPS) contains three types of amino acids (proline, hydroxyproline, and glycine). Incorporation of the OPS into the polyurethane backbone is done to provide a synthetic polymer material with controllable biodegradation properties. As biodegradation processes normally are initiated at the interface between the biomaterial and the living tissue, it is important to characterize the surface composition of biomaterials. ADXPS and ToF-SIMS results show that the surfaces of all four polymers are enriched with the PCL SS, the most hydrophobic component of the three polymer segments.

Preparation of functionalized poly(caprolactone diol)/castor oils blends to be applied as photocrosslinkable tissue adhesives

AbstractPolycaprolactone (PCL) and PCL‐based materials are widely applied in the biomedical field, however, their slow biodegradation profile makes them more suitable to be used in hard tissues, where healing requires longer periods of time. In order to adjust their properties to suit for soft tissues applications, PCL can be blended with other biodegradable materials in order to tune its degradation rate. Herein, polymeric blends of PCL and castor oil (CO) were prepared after their chemical modification with 2‐isocyanatoethylmethacrylate (IEMA) in order to be applied as photocrosslinkable tissue adhesives. These functionalized macromers were chemically characterized and used to prepare polymeric blends (PCL‐IEMA/CO‐IEMA) with variable mass proportions. A biocompatible photoinitiator (Irgacure 2959) was added to these macromers blends which were then irradiated under UV light. The feasibility of the prepared materials as tissue adhesives was evaluated by assessment of their chemical/physical properties as well as their interaction with blood. Moreover, their cytotoxic profile was also evaluated through in vitro studies using human dermal fibroblasts as model cells.

High clarity poly(caprolactone diol)-based polyurethane adhesives for polycarbonate lamination: Effect of isocyanate and chain-extender

The development of a high clarity polyurethane adhesive from a crystalline soft-phase, capable of bonding untreated and ethanolamine surface-treated polycarbonate, is described. A series of polyurethanes were prepared, based on poly(caprolactone diol), selected as the soft-phase as its ester-functionalised backbone structure can assist the adhesive performance. A high crystallinity soft-phase, however, will have an adverse effect on the adhesive's clarity. However, through careful design of the hard-phase architecture, it is possible to address this issue. Eight formulations were synthesised, each with a subtly different hard-phase architecture, created using a combination of methylene diphenyl diisocyanate or isophorone diisocyanate with trimethylol propane only or by including the chain-extenders 2,2-diethyl-1,3-propane diol, 1,3-butane diol and 1,2-propane diol. DSC and FTIR data show that having trimethylol propane alone is not sufficient to disrupt soft-phase crystallisation in the methylene diphenyl diisocyanate formulations, and that for total removal of soft-phase crystallisation a diol chain-extender is required to promote phase mixing within the microphase structure. This reduces peel strengths but values remain above 3 N mm−1 on both untreated and ethanolamine treated polycarbonate after 18 months. More importantly, the change to the morphology markedly improves clarity. In contrast, isophorone diisocyanate systems show poor phase mixing even in the presence of the chain-extenders and, although offering good peel strengths, have low clarity.

One‐pot synthesis of cobalt‐incorporated polyglycerol ester as an antimicrobial agent for polyurethane coatings

ABSTRACTCobalt‐incorporated poly(glycerol ester) (Co–PGE) was synthesized by the polycondensation of glycerol and adipic acid followed by the reaction with cobalt(II) hydroxide under solvent‐free and noncatalyzed one‐pot synthesis conditions. The reaction was monitored through the acid value and hydroxyl value determination. The chemical structure and molecular weight of the poly(glycerol ester) (PGE) and Co–PGE were characterized by Fourier transform infrared spectroscopy, 13C‐NMR, gel permeation chromatography, and inductively coupled plasma mass spectrometry. Co–PGE with a 59.3% degree of branching was incorporated with up to 5.0% w/w cobalt, and it exhibited antimicrobial inhibition against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans in a broth microdilution study. Polyurethane (PU) coatings were prepared by the blending of 0.5–35% w/w Co‐PGE containing with 5% w/w of cobalt with blank PGE, poly(ethylene glycol) with a molecular weight of 6000, poly(caprolactone diol) with a molecular weight of 2000, and additives to react with isophorone diisocyanate. The prepared PUs demonstrated mild to high antimicrobial activities against E. coli, S. aureus, Bacillus subtilis, and C. albicans strains in a disc diffusion test. PU prepared with 0.5% w/w Co–PGE showed a mild inhibition activity against S. aureus, and PU prepared with 10% w/w Co–PGE demonstrated a high inhibition activity against C. albicans. This study demonstrated that value‐added Co–PGE synthesized from glycerol has the potential as an antimicrobial agent for polymer coatings in biomedical devices. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46045.

Surface Thermodynamics of Poly(caprolactone) Diol by Inverse Gas Chromatography

Inverse gas chromatography was applied to evaluate the surface thermodynamic properties of biodegradable poly(caprolactone) diol (PCLD) in the temperature range 313.15–333.15 K with steps of 5 K. The net retention volumes, VN, were determined for the n-alkanes and polar solute probes. Dispersive surface free energy, , was calculated using the Schultz and Dorris-Gray methods, and at T = 313.15 K the values were found to be 19.87 and 21.61 mJm−2 respectively. The dispersive free energy decreased with increase in temperature. Surface Lewis acid parameter, Ka, and Lewis base parameter, Kb, were calculated following Gutmann’s approach. The Ka and Kb values were found to be 0.212 and 0.593 respectively, which revealed the basic nature of PCLD. The three components of the Hansen solubility parameters were determined using for the PCLD surface, and their variation with temperature was studied.

Synthesis and characterization of biocompatible polyurethanes for controlled release of hydrophobic and hydrophilic drugs

Design of biocompatible and biodegradable polymer systems for sustained and controlled release of bioactive agents is critical for numerous biomedical applications. Here, we designed, synthesized, and characterized four polyurethane carrier systems for controlled release of model drugs. These polyurethanes are biocompatible and biodegradable because they consist of biocompatible poly(ethylene glycol) or poly(caprolactone diol) as soft segment, linear aliphatic hexamethylene diisocyanate or symmetrical aliphatic cyclic dicyclohexylmethane-4,4′-diisocyanate as hard segment, and biodegradable urethane linkage. They were characterized with Fourier transform infrared spectroscopy, atomic force microscope, and differential scanning calorimetry, whereas their degradation behaviors were investigated in both phosphate buffered saline and enzymatic solutions. By tuning polyurethane segments, different release profiles of hydrophobic and hydrophilic drugs were obtained in the absence and presence of enzymes. Such difference in release profiles was attributed to a complex interplay among structure, hydrophobicity, and degradability of polyurethanes, the size and hydrophobicity of drugs, and drug-polymer interactions. Different drug-polyurethane combinations modulated the distribution and location of the drugs in polymer matrix, thus inducing different drug release mechanisms. Our results highlight an important role of segmental structure of the polyurethane as an engineering tool to control drug release.

Preparation and properties of castor oil/pentaerythritol triacrylate-based UV curable waterborne polyurethane acrylate

Abstract Castor oil (CO)/pentaerythritol triacrylate (PETA)-based UV curable waterborne polyurethane acrylate (UV-WPUA) was prepared by using isophorone diisocyanate (IPDI), poly(caprolactone diol) (PCL) and dimethylolbutyric acid (DMBA) as the main materials. A series of emulsions and films with different content of CO were obtained. The infrared spectra, together with the nuclear magnetic resonance spectroscopy, demonstrated the presence of CO and PETA in the UV-WPUA chains. The surface roughness of the curing film was measured by atomic force microscope. In addition, the effects of CO content on particle size, thermal properties, glass transition temperature and tensile performance of the emulsions and films were investigated. With the content of CO increasing from 1.72 to 8.58 wt%, the particle size of the UV-WPUA emulsion increased and the particle size distribution gradually widened. The appearance of the emulsions transformed from blue transparent into opaque and the stability decreased gradually. Water resistance, glass transition temperature for soft segment and thermal performance of the films were improved. The tensile strength of the films firstly increased and then decreased.

Preparation and characterization of carboxyl-treated multiwalled carbon nanotube-reinforced shape-memory polyurethane nanocomposites

Shape-memory polyurethane (SMPU) having segmented structure, with 4,4-diphenylmethane diisocyanate as hard segment, poly caprolactone diol 4000 as soft segment, and 1,4-butane diol as chain extender was synthesized using two-step polymerization technique. This pure SMPU was blended with unmodified and modified multiwalled nanotubes (MWNTs), using twin screw extruder and melt spinning technique. X-Ray diffraction, differential scanning calorimetry, morphological analysis, and shape-memory behavior results for the SMPUs are presented in this study. An improvement in the thermal stability and degradation temperature of the SMPU was observed especially in the soft segments, upon 0.1% loading of MWNT. Slight decrease in crystallinity was recorded for MWNT/SMPU as compared to virgin SMPU. The recovery ratio of SMPU fiber increased to 90% with 0.1 wt% loading of MWNT, but the spinnability decreased due to reduced crystallinity and viscosity with an addition of nanotubes to the polyurethane matrix.

Preparation and colloidal properties of an aqueous acetic acid lignin containing polyurethane surfactant

ABSTRACTAqueous acetic acid lignin containing polyurethane (ALPU) surfactants were prepared by the replacement of some hydrophobic poly(caprolactone diol) with different concentrations of multifunctional acetic acid lignin (AL), and with dimethylol propionic acid as the hydrophilic segment. The infrared spectra, together with thermogravimetric analysis, demonstrated the presence of AL in the polyurethane (PU) chains. In addition, the effects of the AL concentration on the particle size, morphology, rheological behavior, and surface activity of the dispersions were investigated. The ALPU particles displayed a spherical morphology. With increasing AL concentration from 0 to 10 wt %, the particle size increased from 36 to 260 nm, and the unimodal distribution was detected for ALPU10 with a 10 wt % AL addition. The viscosity and shear‐thinning behavior of the ALPU dispersions decreased, and the lowest surface tension and critical micelle concentration (cmc) were detected for ALPU10. However, when the AL concentration was 15 wt % (ALPU15), the surface tension and cmc increased. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1855–1862, 2013

Properties of the modified cellulosic fabrics using polyurethane acrylate copolymers

Polyurethane acrylate copolymers (PAC) were synthesized via emulsion polymerization following three step synthesis process using toluene-2,4-diisocyanate, hydroxy terminated poly(caprolactone) diol, 2-hydroxyethylacrylate (HEA) and butyl acrylate (BuA). Structural characteristics of the synthesized polyurethane acrylate copolymer (PAC) were studied using Fourier Transform Infrared (FT-IR) spectrophotometer and are with accordance with the proposed PAC structure. The physicochemical properties such as solid contents (%), tackiness, film appearance and emulsion stability were studied, discussed and co-related with other findings. The plain weave poly-cotton printed fabrics after application of PAC was evaluated applying colorfastness standard test method. The results revealed that emulsion stability is the main controlling factor of the synthesized material in order to get better applications and properties. The emulsion stability of the synthesized material increased with increase in molecular weight of the polycaprolactone diol.

Surface modification of recording electrodes

Waterborne Polyurethanes (PUs) are a family of polymers that contains urethane linkages synthesized in an aqueous environment and are thus free of organic solvents. Recently, waterborne PUs have been extensively studied for biomedical applications because of their biocompatibility. The present work investigates the following: (1) the impact on electrical performance of electrode materials (platinum and silicon) modified chemically by a layer of waterborne PU, and (2) the behavior of rat cardiac fibroblasts and rat cardiomyocytes when in contact with an electrode surface. Diisocyanate and poly(caprolactone diol) were the main reagents for producing PUs. The electrochemical impedance of the electrode/electrolyte interface was accessed by electrochemical impedance spectroscopy. The cellular viability, proliferation, and morphology changes were investigated using an MTT assay. Cardiomyocyte adherence was observed by scanning electron microscopy. The obtained surface was uniform, flat, and transparent. The film showed good adhesion, and no peeling was detected. The electrochemical impedance decreased over time and was influenced by the ionic permeability of the PU layer. The five samples did not show cytotoxicity when in contact with neonatal rat cells.

Shape‐memory anchoring system for bladder sensors

In this work, we propose the use of shape-memory polymer as an anchoring system for a bladder sensor. The anchoring system was designed from a biomedical biodegradable water-based poly(ester-urethane) produced in an aqueous environment by using isophorone diisocyanate/hydrazine (hard segment) and poly(caprolactone diol)/2,2-bis (hydroxymethyl) propionic acid (soft segment) as the main reagents. Tensile strength and elongation-at-break deterioration upon degradation in synthetic urine were investigated. In-body shape recovery was simulated and measured in synthetic urine. Results indicated that shape recovery can occur at body temperature and expulsion of the sensor by the body along with urine may occur through the combined effect of urine hydrolytic attack and compression exerted by the bladder walls.

Proliferation of human mesenchymal stem cells derived from adipose tissue on polyurethanes with tunable biodegradability

Polyurethanes (PUs) have been considered good candidates to be used in biomedical temporary devices that require mechanical properties comparable to soft tissues. However, toxicity of some PUs is still a concern, since these polyurethanes can contain potential toxic components and residual organic solvents derived from their synthesis. In this work, in vitro tests to measure viability and proliferation of human mesenchymal stem cells (hMSCs) in contact with PUs with tunable biodegradability were performed by employing MTT, alkaline phosphatase and collagen secretion assays. PUs were produced in an aqueous environment by employing isophorone diisocyanate/hydrazine (hard segment) and poly(caprolactone diol)/2,2-bis (hydroxymethyl) propionic acid (soft segment) as the main reagents. Three series of PUs having different soft segment contents were synthesized. These PUs had their chemical structure, morphology and hydrolytic degradation investigated. The rate of hydrolysis of the obtained PUs was tailored by modifying the soft segment content of the polymers. In vitro results showed that PUs can provide a satisfactory environment for the adhesion and proliferation of hMSCs.

Influence of structure of organic modifiers and polyurethane on the clay dispersion in nanocomposites via in situ polymerization

AbstractInfluence of polyurethane (PU) structure on the nature of PU/clay nanocomposite was studied using varying amounts of trimethylol propane (TMP) as branching agent. The effect of hydroxyl groups in the modifier of organoclays on the structure of PU/clay nanocomposites was studied. Nanocomposites were characterized using wide‐angle X‐ray diffraction measurements (WAXD) and transmission electron microscopy (TEM). The results show that formation of completely exfoliated and well dispersed polyurethane/clay nanocomposites via in situ polymerization, is facilitated by the presence of tethering groups on the clay surface and an ability to form branched and crosslinked structures. Incorporation of long alkyl chains in addition to tethering hydroxyl groups in the modifier structure of the clay did not significantly improve the compatibility of linear PU with the clay. Intercalated thermoplastic polyurethane/clay nanocomposites, prepared using poly(caprolactone diol) as soft segment and isophorone diisocyanate and 1,4‐butanediol as hard segments show increase in storage tensile moduli at temperatures before glass transition temperature when functional groups capable of chemically reacting with the growing polymer chains are present in the clay modifier. This is indicative of improved interaction of the polymer with the clay surface when the modifier has larger number of hydroxyl groups. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Photopolymerizable and injectable polyurethanes for biomedical applications: Synthesis and biocompatibility

Two types of photopolymerizable and injectable polyurethane acrylates (PUAs), based on poly(propylene glycol) or poly(caprolactone diol) and hydroxyethyl methacrylate, were synthesized and characterized in order to obtain information regarding their use as an injectable material for biomedical applications. Structural characteristics of the biomaterials, including the degree of phase separation, were evaluated by Fourier transform infrared spectroscopy. The viscosities of the obtained biomaterials make them suitable for injection, molding and photopolymerization using visible light, as demonstrated by the injection test. The cured polymers had mechanical properties comparable to those of certain soft tissues, such as skin. An in vitro cell-polyurethane cytotoxicity study was carried out with mesenchymal stem cells from rat tibias and femurs. The proliferation/viability of the cells in the presence of the synthesized material was assessed by the MTT assay, collagen synthesis analysis and the expression of alkaline phosphatase. The results that were obtained through the in vitro tests indicated that PUAs are cytocompatible. The in vivo experiments were correlated with the in vitro tests and showed low levels of toxicity for the obtained biomaterials. Histology cross-sections showed that the biomaterials induced no significant inflammatory reaction. Our study demonstrates the potential for using synthesized photocurable polyurethanes in biomedical applications. Furthermore, the obtained injectable polymer systems employ minimally invasive procedures and can be molded in situ before photopolymerization with visible light.

Synthesis and characterization of biodegradable interpenetrating polymer networks based on gelatin and divinyl ester synthesized from poly(caprolactone diol)

AbstractThis article describes the synthesis and characterization of interpenetrating polymer networks (IPNs) from hydrophilic and hydrophobic polymers using emulsification technique. Tween 20 (0.001 wt % of gelatin) was employed as emulsifier for the preparation of semi and full IPNs. Gelatin (G), a hydrophilic component was crosslinked by glutaraldehyde (Glu) and divinyl ester (DVE), a hydrophobic component was polymerized/crosslinked using 3 mol % of AIBN as an initiator. Structural characterization was done using FTIR (doublet at 1620 and 1636 cm−1) and NMR (signals in the range of δ = 5–7 ppm), which confirmed the formation of DVE. Several samples were prepared by varying the ratio of gelatin : DVE (w/w) and the Glu concentration. The swelling characteristics (as a function of varying pH maintained using buffers) and degradation behavior (in phosphate buffer saline pH 7.4) of hydrogels was studied to investigate the effect of composition and crosslinker concentration. Percent water uptake decreased from 496 to 181 at pH 7.4 and pH 6.5 in IPNs as the concentration of DVE increased from 0.3 g to 0.7 g per g of gelatin. Semi‐IPNs, where DVE was not polymerized, demonstrated higher swelling at pH 7.4 in contrast to pH 6.5 irrespective of Glu concentration. Gelatin hydrogels degraded within 180 h and IPNs degraded within 290 h whereas DVE did not degrade till the study period of 20 days. The formation of IPN was confirmed by thermal characterization (DSC, TGA) and scanning electron microscopy (SEM). Observation of cross‐sectional microstructure of disrupted honeycomb of Gx into closely packed fiber‐like structure upon interpenetration by SEM clearly suggests the formation of IPN. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009