Polycaprolactone Glycol Research Articles

Effect of Soft Segment Structures on the Properties of Self‐Healing Photopolymerizable Thiocarbamate‐Based Polyurethanes

ABSTRACTThree self‐healing photopolymerizable thiocarbamate‐based polyurethane oligomers were synthesized using different macromolecular chain extenders: polypropylene glycol (PPG‐1000), polytetrahydrofuran (PTMG‐1000), and polycaprolactone glycol (PCL‐1000). The variations in the soft segment structures had minimal impact on the double bond conversion and gel fraction of the light‐cured self‐healing thiocarbamate‐based polyurethane materials, achieving double bond conversion rates and gel fractions exceeding 87%. Incorporating polycaprolactone diol as the soft segment improved heat resistance and tensile stress but reduced the material's self‐healing ability. Conversely, utilizing polytetrahydrofuran as the soft segment resulted in outstanding overall performance, notably lowering the glass transition temperature to −48.4°C, increasing tensile strain to 1280%, achieving a self‐healing efficiency of up to 90%, and exhibiting good degradation properties.

Biodegradable Polyurethane Scaffolds in Regeneration Therapy: Characterization and In Vivo Real-Time Degradation Monitoring by Grafted Fluorescent Tracer.

There is an urgent need to assess material degradation in situ and in real time for their promising application in regeneration therapy. However, traditional monitoring methods in vitro cannot always profile the complicated behavior in vivo. This study designed and synthesized a new biodegradable polyurethane (PU-P) scaffold with polycaprolactone glycol, isophorone diisocyanate, and l-lysine ethyl ester dihydrochloride. To monitor the degradation process of PU-P, calcein was introduced into the backbone (PU-5) as a chromophore tracing in different sites of the body and undegradable fluorescent scaffold (CPU-5) as the control group. Both PU-P and PU-5 can be enzymatically degraded, and the degradation products are molecularly small and biosafe. Meanwhile, by virtue of calcein anchoring with urethane, polymer chains of PU-5 have maintained the conformational stability and extended the system conjugation, raising a structure-induced emission effect that successfully achieved a significant enhancement in the fluorescence intensity better than pristine calcein. Evidently, unlike the weak fluorescent response of CPU-5, PU-5 and its degradation can be clearly imaged and monitored in real time after implantation in the subcutaneous tissue of nude mice. Meanwhile, the in situ osteogeneration has also been promoted after the two degradable scaffolds have been implanted in the rabbit femoral condyles and degraded with time. To sum up, the strategy of underpinning tracers into degradable polymer chains provides a possible and effective way for real-time monitoring of the degradation process of implants in vivo.

Structure and performance control of high‐damping bio‐based thermoplastic polyurethane

AbstractThermoplastic polyurethane (TPU) has become the focus of attention in the green and sustainable materials field because of its superior processability and recyclability. In this paper, a series of polylactic acid (PLA) and polycaprolactone (PCL)‐based TPUs were successfully prepared by selecting PLA glycol, PCL glycol, isophorone diisocyanate (IPDI) and 1,4‐butanediol (BDO) through a one‐step polymerization method. The properties of the PLA and PCL‐based TPUs are comprehensively characterized by Fourier transform infrared spectroscopy, 1H NMR spectra, gel permeation chromatography, differential scanning calorimetry, thermalgravimetric analyzer, tensile test, dynamic mechanical analysis, scanning electron microscope, and so forth. The effect of hard segments content and PLA glycol molecular weight on the properties of PLA and PCL‐based TPUs was systematically studied. Notably, their performance shows a certain degree of regularity and can be controlled by adjusting the hard segments content or the molecular weight of the PLA glycol. The prepared PLA and PCL‐based TPUs have a tensile strength of 24.71 MPa, excellent thermal stability and out‐standing damping performance. Its tan δ max of 1.40 and an effective damping temperature range of 50°C also make it a green damping material with great potential.

Preparation and Characterization of Glucose and Sulfamate Double‐Modified Biodegradable Waterborne Polyurethane

AbstractA kind of glucose and sulfamate double‐modified waterborne polyurethane (WPU) was synthesized by using glucose (GLC) and N‐[(2‐amionoethyl)‐amino] ethane sulphonated sodium (AAS) as internal crosslinking agent, polycaprolactone glycol (PCL) as soft segment, 2,2‐bis(hydroxymethyl) propionic acid (DMPA) and N‐[(2‐amionoethyl)‐amino] ethane sulphonated sodium (AAS) as hydrophilic monomers. The influences of AAS and GLC content on the WPU structure and properties were analyzed and characterized by high speed of centrifugation, particle size examination, ATR‐FTIR, TEM, DMA, TGA, SEM, tensile tests, contact angle, water uptake and degradation measurements. The test results indicated that the modified biodegradable WPU had great comprehensive properties. Compared with the unmodified polyurethane, the prepared cross‐linked WPU had a good stability (over 6 months), outstanding mechanical strength (51.55 MPa for WPU4 films) and biodegradability (the weight loss in soil and PBS/lipase reached 25.2 % and 11.8 % for 6 weeks), which made them appropriate supplements for the traditional waterborne polyurethanes in the future.

Waterborne Polyurethane Coatings with Covalently Linked Black Dye Sudan Black B.

Colored waterborne polyurethanes have been widely used in paintings, leathers, textiles, and coatings. Here, a series of black waterborne polyurethanes (WPUs) with different ratios of black dye, Sudan Black B (SDB), were prepared by step-growth polymerization. WPU emulsions as obtained exhibit low particle sizes and remarkable storage stability at the same time. At different dye loadings, essential structural, statistical and thermal properties are characterized. FTIR (fourier transform infrared) spectra indicate that SDB is covalently linked into waterborne polyurethane chains. All of the WPUs with covalently linked SDB show better color fastness and resistance of thermal migration than those with SDB mixed physically. Besides, WPUs incorporated SDB covalently with different polymeric diols, polytetramethylene ether glycol (PTMG), polypropylene glycol (PPG), poly-1, 4-butylene adipate glycol (PBA) and polycaprolactone glycol (PCL), were prepared to obtain different properties to cater to a variety of practical demands. By a spraying method, the black WPUs can be directly used as metal coatings without complex dyeing process by simply mixing coating additive and other waterborne resins, which exhibit excellent coating performance.

Towards optimization of odonto/osteogenic bioengineering: in vitro comparison of simvastatin, sodium fluoride, melanocyte-stimulating hormone.

Tissue engineering has emerged as a potential therapeutic option for dental problems in recent years. One of the policies in tissue engineering is to use both scaffolds and additive factors for enhancing cell responses. This study aims to evaluate and compare the effect of three types of biofactors on poly-caprolactone-poly-ethylene glycol-poly caprolactone (PCL-PEG-PCL) nanofibrous scaffold on human dental pulp stem cell (hDPSCs) engineering. The PCL-PEG-PCL copolymer was synthesized with ring opening polymerization method, and its nanofiber scaffold was prepared by electrospinning method. Nanofibrous scaffold-seeded hDPSCs were treated with sodium fluoride (NaF), melanocyte-stimulating hormone (MSH), or simvastatin (SIM). Non-treated nanofiber seeded cells were utilized as control. The viability, biocompatibility, adhesion, proliferation rate, morphology, osteo/odontogenic potential, and the expression of tissue-specific genes were studied. The results showed that significant higher results demonstrated significant higher adhesive behavior, viability, alizarin red activity, and dentin specific gene expression in MSH- and SIM-treated cells (p<0.05). This study is unique; in that, it compares the effects of different treatments for optimization of dental tissue engineering.

The effect of PETA/PETTA composite system on the performance of UV curable waterborne polyurethane acrylate

ABSTRACTUV curable waterborne polyurethane acrylate based on pentaerythritol triacrylate (PETA)/pentaerythritol tetraacrylate (PETTA) composite system was prepared by using polycaprolactone glycol (PCL), isophorone diisocyanate (IPDI), β‐cyclodextrin (β‐CD) and 2,2‐dimethylol butanoic acid (DMBA) as the main materials. Besides, PETA was used as capping agent and PETTA was used as reactive diluent. By varying the additive amount of PETA and PETTA, a series of emulsions and films were obtained. The molecular structure was characterized by infrared spectra and a series of performance tests such as particle size, contact angle, tensile properties, UV curing performance, differential scanning calorimetry and thermogravimetric analysis were conducted. The result showed that more compact network structure was formed by introducing PETTA with higher reactivity into the polyurethane molecule under UV irradiation and many performances were improved as a whole. However, there existed phase separation to a certain extent. Especially when the content of PETTA was higher than 83.33%, the effect of compatibility became more prominent. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41262.

Preparation and Application of Blocked &amp;amp; Crosslinked Waterborne Polyurethane Microemulsion as Paper Strengthening Agent

By means of self-emulsifying, blocked &amp; crosslinked cationic polyurethane (CBPU) microemulsion was prepared with isophorone diisocyanate (IPDI), polycaprolactone glycol, bisphenol A, methyldiethanolamine (MDEA) as cationic hydrophilic chain-extending agent, ̴̵̹̹̱̼̽͊̿˰̱̓˰̷̲̼̳̻̹̿̾˰̷̵̱̾̈́˰̴̱̾˰̞˽̫˸́˼́˽̴̵̸̹͉̼̽̈́˽̂˽̵̱̳͉̼̈́˹̵̸͉̼̭̈́˽ڂ˽̴̸̴̵̸̹͉͈͉͉̼̱̹͂̿̈́̽̾̿˰̴̵̱̱̹̀͂̿̀̾̽˸̠̔̔˹˰̱̓˰̷̳̼̹̻̹͂̿̓̓̾̾˰̷̵̱̾̈́˾˰̶̶̵̳̈́̓̕˰̶̿˰̸̵̈́˰̠̥̓̒˰̵̴̲̼̳̻̿˰̱̹͂̈́̿˰̿̾˰̸̵̈́˰̸͉̹̳̱̼̀̓˰̵̵̹̀͂̿̀͂̈́̓˰̶̿˰̸̵̈́˰̵̵̴̱̈́͂̈́˰̵̱̀̀͂˰̵̵͇͂˰̴̵̴̹̓̈́ͅ˾˰̸̵̤˰̵̵̵͈̹̱̼̀͂̽̾̈́˰̵̼͂̓̈́̓ͅ˰̸͇̓̿˰̓̈́͂uctures of tertiary amine group, imidazole ring and urethane group are found in CBPU molecular structure. The morphology of the particle is uniform spheric structure and its size is related to the content of tertiary amine groups of CBPU. The paper strength, especially the wet strength can be obviously increased with the increasing of the blocked ratio of CBPU. The optimum blocked ratio of CBPU is 10%.

Preparation and application of cationic blocked waterborne polyurethane as paper strength agent

Cationic blocked waterborne polyurethane (CBWPU) as paper strength agent was prepared by the reaction of N-[(1,1-dimethyl-2-acetyl)ethyl]-β-dihydroxyethylamino propanamide(DDP), isophorone diisocyanate(IPDI), polycaprolactone glycol(PCL) and bisphenol A, with imidazole as blocking agent and N-methyldiethanolamine as hydrophilic chain-extending agent. Effects of the blocked ratio and the dosage of CBWPU on the physical properties of the treated paper were studied. The chemical structure of CBWPU and the surface morphology of the paper surface are characterized by Fourier transform infared spectrometer(FT-IR) spectra and scanning electron microscopy(SEM). The results show that the paper strength, especially the wet tensile index and the wet strength of paper can be obviously improved with the increasing of the blocked ratio and the dosage of CBWPU. FT-IR result shows that structures of tertiary amine group, imidazole ring and urethane group are found in CBWPU molecular structure. SEM obsevation of the treated paper reveals that the exiestence of a lot of filamentous materials and films, which can improve the crosslinking between fibers.

Novel triol-crosslinked polyurethanes and their thermorheological characterization as shape-memory materials

A new family of crosslinked polyurethanes was synthesized and characterized as shape-memory polymers. Three-arm network junctions are provided by 1,1,1-trimethylol propane with an isocyanate group on each arm. Three diisocyanates are used: 4,4′-methylene bis(phenyl isocyanate), toluene diisocyanate, and 4,4′-dibenzyl diisocyanate. They are linked together by macrodiol soft segments formed from either polytetrahydrofuran with molar mass of 650, 1000 or 2000 g mol −1 or polycaprolactone glycol with molar mass of 830 or 1250 g mol −1. Thermorheological response of each polymer was characterized by tensile creep tests through the glass transition of the soft segments, to obtain the linear viscoelastic retardation spectrum, limiting compliances and time–temperature shift factor. These were used to predict significant features of shape-memory performance. With a decrease in soft segment chain length, the temperature of maximum shape recovery rate increased and the width of the recovery window decreased, consistent with loss of soft segment chain mobility remote from the crosslinks. Tensile modulus in the switched condition (above T g) was 8–16 MPa, increasing with crosslink density and hard-segment rigidity. The results confirmed the potential of these polyurethanes as a new family of tunable shape-memory materials.

Water vapor permeability of cotton fabrics coated with shape memory polyurethane

In this paper, we have investigated the water vapor permeability of shape memory polyurethane (SMPU) coated cotton fabrics. The SMPUs were tailor made in order to obtain the phase transition temperature (soft segment crystal melting temperature) in the room temperature range. SEM studies were carried out in order to investigate the surface structure of coated and uncoated fabrics. The temperature sensitive water vapor permeability at soft segment crystal melting point was observed for SMPU coated fabrics. When the experimental temperature reached the soft segment crystal temperature of SMPU, an abrupt change of water vapor permeability of SMPU coated fabrics were observed. The significant change of water vapor permeability of SMPU coated fabrics is due to the phase change of SMPU which causes density changes inside the membranes due to micro-Brownian motion of soft segment, therefore, enhanced the water vapor permeability through the coated fabrics. The water vapor permeability of coated fabrics was also dependent on the primary structure of SMPU. When polycaprolactone glycol (PCL, M n 3000 g mol −1) was introduced in the polytetramethylene glycol (PTMG, M n 2900 g mol −1) based SMPU, the water vapor permeability decreases due to the increased interaction between the polymer chains due to presence of ester groups. In contrast increase of polyethylene glycol ( M n 3400 g mol −1) in the SMPU backbone, the WVP increases due to the increasing hydrophilicity of the SMPU.

Structural characterization and mass transfer properties of polyurethane block copolymer: influence of mixed soft segment block and crystal melting temperature

AbstractAn attempt has been made to investigate the influence of mixed soft segment on structure and mass transfer properties of segmented polyurethane (SPU). For this purpose polyurethane block copolymer containing soft segment such as polycaprolactone glycol (number‐average molecular weight 3000, PCL 3000), PCL 3000–polypropylene glycol (number‐average molecular weight 3000, PPG 3000), PCL 3000–polytetramethylene glycol (number‐average molecular weight 2900, PTMG 2900), PPG 3000–PTMG 2900, were synthesized using a two‐step or three‐step synthesis process. All the SPUs were modified with the hydrophilic segment, i.e. diol‐terminated poly(ethylene oxide) (number‐average molecular weight 3400, PEG 3400). Fourier‐transform infrared, wide‐angle X‐ray diffraction, differential scanning calorimetry, and dynamic mechanical thermal analysis were used to characterize the polyurethanes. The mass transfer properties were measured by equilibrium sorption and water vapor permeability measurements. Mixed blocks loosen the inter‐chain interaction due to phase mixing which decreases the crystallization of the soft segment in the resulting SPU. The crystallinity of mixed polyol block SPU increases when both polyols are crystallizable in the pure state. Highest loss tan δ value was observed for the sample containing PTMG 2900–PPG 3000 mixed soft segment due to their flexible and phase mixed structure which increases the chain mobility; this sample performed best among all four SPUs in equilibrium water sorption as well as water vapor permeability owing to their loose and nearly amorphous structure. Soft segment crystal melting further enhances the water vapor permeability significantly, which would make the membrane suitable for breathable textiles, packaging and medical applications. Copyright © 2006 Society of Chemical Industry

Microphase-separated structure and mechanical properties of novel polyurethane elastomers prepared with ether based diisocyanate

A diisocyanate baring ether bonds, 1,2-bis(isocyanate)ethoxyethane (TEGDI), was used for the preparation of polyurethane elastomers (PUEs). The PUEs were synthesized with either TEGDI or HDI, poly(oxytetramethylene) glycol (PTMG), and curing agents by a prepolymer method. 1,6-Hexamethylene diisocyanate (HDI) was also used as a control diisocyanate. The TEGDI-based PUEs exhibited highly softened property on account of flexibility of TEGDI itself and weaker phase separation. Another TEGDI-based PUEs were prepared with either poly(oxypropylene) glycol (PPG) or poly(caprolactone) glycol (PCL). Microphase-separated structure of these TEGDI-based PUEs are quite different from those with general diisocyanates and the PUEs were made be greatly softened.

Thermal Degradation of Polyurethane Elastomers: Determination of Kinetic Parameters

The objective of this study is determining the kinetic parameters of thermal degradation of polyurethane elastomers before and after UV irradiation. To determine the kinetic parameters of elastomeric polyurethane (PUR) decomposition the Freeman-Carroll method of calculation is applied. The effect of soft segment and hard segment type, soft segment molecular weight and hard segment content on the kinetic parameters of the degradation process were measured. Polyurethane elastomers were obtained from poly(oxytetramethylene) glycol, PTMO, of 1000 and 2000 molecular weight and polycaprolactone glycol of 1250 molecular weight (PCL), 4,40diphenylmethan diisocyanate (MDI) and 4,40-dicyclohexylmethane diisocyanate (H12MDI) and 1,4-butanediol as chain extender. The activation energy values obtained for PUR elastomers based on polyester soft segment were higher than those based on polyether soft segment.The PUR elastomers based on aromatic type of diisocyanate have lower activation energy values than those based on cycloaliphatic type of diisocyanate.

Preparation and properties of waterborne polyurethanes for water‐vapor‐permeable coating materials

AbstractWaterborne polyurethanes were prepared by polyaddition reaction using isophorone diisocyanate, dimethylol propionic acid, various polyols with a fixed molecular weight (Mn = about 2000), ethylene diamine as a chain extender, and triethylamine as a neutralization agent. Three types of polyols such as (1) solo glycols [polypropylene glycol (PPG) (Mn = 2000), poly(tetramethylene oxide) glycol (PTMG) (Mn = 2000), poly(tetramethylene adipate glycol) (PTAd) (Mn = 2000), or polycaprolactone glycol (PCL) (Mn = 2000)], (2) the polyol blends (PPG/PCL, PTMG/PCL, PPG/PTAd, PTMG/PTAd), and (3) a triblock glycol (TBG) (Mn = 1990) were used in this study. The triblock glycol (TBG) [(CL)4.5–PTMG (Mn = 1000)–(CL)4.5 (Mn =1990] was synthesized from PTMG and ϵ‐caprolactone (CL) in this study. The triblock glycol was found to have two main melting peaks at about 13 and 40°C. This study was examined on the effect of the types of polyols on the particle size, viscosity, dynamic thermal properties, and water vapor permeability. The particle size of the aqueous polyurethane–urea dispersion increased in the order of polyol‐blends‐based samples (183–350 nm) &gt; TBG‐based sample (167 nm) &gt; solo‐polyol‐based sample (58–96 nm). By dynamic thermal mechanical analysis, the ester‐type polyol‐ (PTAd and PCL) based samples were found to have higher storage modulus and Tg than those of ether‐type polyol‐ (PPG and PTMG) based samples. The water vapor permeability (WVP) increased in the order of TGB‐based sample &gt; PCL/PTMG‐based sample &gt; PTAd/PTMG‐based sample &gt; PCL/PPG‐based sample &gt; PTAd/PPG‐based sample &gt; PTMG‐based sample &gt; PPG‐based sample &gt; PCL‐based sample &gt; PTAd‐based sample. WVP was found to increase in the order of TBG‐based sample &gt; polyol‐blend based samples &gt; solo‐polyol‐based samples. It was also found that the samples containing ether‐type glycols (PTMG, PPG) had higher permeability than samples having ester‐type glycols (PCL, PTAd). PTMG‐based samples were found to have higher permeability than PPG‐based samples if other compositions were constant. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 123–129, 2003

In vitro biocompatibility of fluorinated polyurethanes

The in vitro biocompatibility of fluorinated polyurethanes (FPUs), labelled as FPU 42, 52, 58, and 60, was evaluated by means of thrombogenicity, cytoxicity and cytocompatibility tests. Cardiothane® was taken as control material. The thrombogenicity was tested on thin material films by measuring the activation of prekallikrein (PKK) to kallikrein (KK). Level I cytoxicity tests of the bulk materials, i.e. Neutral Red (NR) uptake, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), and Kenacid Blue (KB) assays, were performed to assess the influence of the polymer extracts on, respectively, lysosomes, mitochondria and cell proliferation. The cytocompatibility was evaluated, on thin membranes made by a spraying phase-inversion process, by measuring the area of the polymer surface covered by human umbilical vein endothelial cells (HUVEC) 1 week after seeding. The results indicate that all the polymers are not thrombogenic, and not cytotoxic. The FPUs that contain polycaprolactone glycol (PCLG) (FPU 52 and 60) instead of poly (tetramethylene ether) glycol (PTMEG) (FPU 42 and 58) as soft segment show the lowest thrombogenicity and the best cytocompatibility.

Synthesis and characterization of isophorone diisocyanate based polyurethanes

Polyurethane ionomers based on polycaprolactone glycol or polyoxytetramethylene glycol with isophorone diisocyanate and chain extenders 1,4-butanediol, 2,2′(dihydroxymethyl) propionic acid and in some cases water, were synthesized in solution. Stable aqueous dispersions from the ionomers were obtained when the concentration of ionic groups was at least 30 mmol per 100 g of polyurethane. Higher concentration of hard segments in the structure produced elastic and transparent films. Hard-soft segment interactions in a series of model compounds were estimated by Fourier transform infrared spectroscopy. Thermal properties of the films were determined by differential scanning calorimetry and by FTIR as well.

Polyurethane anionomers. I. Structure properties of polyurethane anionomers

AbstractThe influence of mono and divalent nontransition and transition metals on the glass transition and mechanical properties of polyurethane anionomers have been investigated. NCO‐terminated prepolymer prepared from 4,4′‐methylene‐bis(phenyl isocyanate) (MDI) and poly(caprolactone) glycol (PCL) was chain extended with dimethylolpropionic acid (DMPA), and the anionomers obtained by neutralization of the prepolymer. The glass transition temperatures of polyurethane anionomers have been studied as a function of the counterion. From simple electrostatic considerations, it is shown that a linear relationship exists between the glass transition temperature and ionic potential (ϕ) for these particular materials. The relation is; Tg = Aϕ + B. The mechanical properties are greatly affected by the type of the counterion, and in some cases, such as monovalent and nontransition metals, the mechanical properties of the anionomers improved by increasing the ionic potential. On the other hand, transition metals containing anionomers exhibited good mechanical properties but no relationship was observed between the mechanical properties and the ionic potential. The extent of water absorption of PU anionomers follows the same relative trends as the tensile strengths of the transition metals with filled and partially filled d‐orbitals.