Synthesis and characterization of caprolactone based polyurethane with degradable and antifouling performance

In this work,a degradable polyurethane composed of caprolactone(CL)and L-Lactide(LLA)as soft segments,and 4,40-methylenebis(cyclohexyl isocyanate)(H12 MDI)and polytetramethylene ether glycol(PTMEG)as hard segments,was prepared.Hydrolytic degradation experiment revealed that the degradable polyurethane(PU)could be degraded in artificial seawater.It also showed that caprolactone-copolyurethane(CL-PU)copolymer with higher crystallinity degraded much slower in artificial seawater.However,the introduction of LLA resulted in an increase in the hydrophilicity and reduction in the crystallinity of degradable PU,as demonstrated by the contact angle analysis.The result of the scanning electron microscope showed that the surface of degradable PU renewed under static condition.Moreover,degradable PU was able to be used as a carrier,and it controlled the release rate of 4,5-dichloro-2-octyl-isothiazolone(DCOIT).The anti-diatom(Navicula incerta)test demonstrated that the(caprolactone-co-L-lactide)-co-polyurethane 4(CL/LAx-PU4)with DCOIT contents prevented the adhesion of diatom Navicula incerta(88.37%reduction)due to their self-polishing and the release of antifoulants.Therefore,the degradable PU consisted of CL,LLA,and DCOIT could be a durable resin with good antifouling activity for the application in the marine anti-biofouling field.

EPITAXIAL CRYSTALLIZATION OF POLY(ε-CAPROLACTONE)ON HIGHLY ORIENTED ISOTACTIC POLYPROPYLENE

Electron microscope and electron diffraction have been used to study epitaxial crystallization of poly(ε-caprolactone)(PCL).on highly oriented film of isotactic polypropylene(iPP).The results obtained from bright field(BF)electron micrograph and electron diffraction indicate that the PCL can epitaxially grow on iPP substrate and form cross-hatched lamellar texture.The c axes of PCL are ±500 apart from the c axes of iPP. The contact planes of the two kinds of crystals are(010)of iPP and(100) of PCL,respectively.

MONOMERIC INTERACTION BETWEEN ETHYLENE-TEREPHTHALATE AND CAPROLACTONE

The miscibility of poly(ethylene terephthalate (ET)- caprolactone (CL) (TCL)/poly(ethylene terephthalate) (PET) blends were examined by Differential Scanning Calorimeter (DSC). In these blends, a miscibility limit specified by ET content in the TCL was found to be about 70 (wt%). In the blends of TCL/TCL with different ET contents, a miscibility window defined by ET content was also found to range from 82 to 58 (wt%). Based on the experimental miscibility limits and the mean field binary interaction model, the interaction parameter between monomeric units of ET and CL was obtained.

Synthesis, Crystal Structure of [(MeC_5H_4)_2Ln(μ-OCH_2CH_2NMe_2)]_2 (Ln=Sm, Y, Nd) and Their Catalytic Activity for Ring-Opening Polymerization of ε-Caprolactone

Reaction of (MeC 5H 4) 3Ln with HOCH 2CH 2NMe 2 in tetrahydrofuran(THF) gives the new complexes [(MeC 5H 4) 2Ln(μ OCH 2CH 2NMe 2)] 2 (Ln=Sm, Y, Nd) with nitrogen functionalized μ alkoxide ligand. The complexes were characterized by elemental analysis and IR, and [(MeC 5H 4) 2Sm(μ OCH 2CH 2NMe 2)] 2 was structurally characterized by the X ray diffraction to be a dimer formed by two unsymmetric oxygen bridges. The complex has a tricyclic skeleton with the additional two Sm-N bonds via intramolecular coordination of OCH 2CH 2NMe 2. The coordination number of the central metal Sm is nine. The title complexes show good catalytic activity for ring opening polymerization of ε caprolactone.

Electrospun Small Diameter Tubes to Mimic Mechanical Properties of Native Blood Vessels Using Poly (L-lactide-co-ε-caprolactone )and Silk Fibroin: a Preliminary Study

Mismatch in mechanical properties can induce intimal hyperplasia,which is one of the main reasons for the failure of small diameter artificial blood vessels. Electrospun small diameter tubes with tailored mechanical properties were fabricated through blending poly( L-lactide-co-ε-caprolactone)( PLCL) and silk fibroin( SF)with the mass ratios of 30 /70,50 /50,and 70 /30 in this study.Scanning electron microscopy( SEM) and mechanical testing were used to characterize morphological and mechanical properties of the tubes. Results showed that tensile strength of the tubes was higher than most of the native blood vessels,and elongations at break of them were improved greatly by blending PLCL. Compliances of the tubes were all higher than 1% /13. 33 kPa( 1% /100 mmHg).Particularly,tubes with blending mass ratio of 50 /50 showed similar compliance with human native femoral arteries,which provided a promising biomaterial that could be applied on small diameter vascular applications.

Biomimetic three-layered membranes comprising(poly)-e-caprolactone,collagen and mineralized collagen for guided bone regeneration

The distinct structural properties and osteogenic capacity are important aspects to be taken into account when developing guided bone regeneration membranes.Herein,inspired by the structure and function of natural periosteum,we designed and fabricated using electrospinning a fibrous membrane comprising(poly)-e-caprolactone(PCL),collagen-I(Col)and mineralized Col(MC).The three-layer membranes,having PCL as the outer layer,PCL/Col as the middle layer and PCL/Col/MC in different ratios(5/2.5/2.5(PCM-1);3.3/3.3/3.3(PCM-2);4/4/4(PCM-3)(%,w/w/w))as the inner layer,were produced.The physiochemical properties of the different layers were investigated and a good integration between the layers was observed.The three-layeredmembranes showed tensile properties in the range of those of natural periosteum.Moreover,the membranes exhibited excellent water absorption capability without changes of the thickness.In vitro experiments showed that the inner layer of the membranes supported attachment,proliferation,ingrowth and osteogenic differentiation of human bone marrowderived stromal cells.In particular cells cultured on PCM-2 exhibited a significantly higher expression of osteogenesis-related proteins.The three-layered membranes successfully supported new bone formation inside a critical-size cranial defect in rats,with PCM-3 being the most efficient.The membranes developed here are promising candidates for guided bone regeneration applications.

Synthesis and Characterization of Monomeric Salicylaldiminato Lanthanide Complexes and Their Catalytic Behavior for Polymerization of ε-Caprolactone

Anhydrous LnCl 3 reacts with 2 equiv. of the sodium salt of the bidentate Schiff base N (2,6 diisopropylphenyl)salicylaldimine in THF to form the monomeric lanthanide chlorides [2 OC 6H 4CH= N(2,6 i Pr 2C 6H 3) ] 2LnCl(THF) [Ln=Yb (1), Er (2)]. Complex 1 crystallizes in P 1 space group with a =0 9215(2) nm, b = 1 36612(4) nm, c =1 6899(2) nm, α =74 83(3)°, β = 77 43(2)°, γ =81 04(1)°, Z =2, V =1 9929(4) nm 3, D c=1 402 g/cm 3. The two complexes exhibited fairly good catalytic activity in the ring opening polymerization of ε caprolactone.

Lanthanocene Diolate Complexes: Synthesis, Structures and Catalytic Property for ε-Caprolactone Polymerization

Reaction of LnCl3 first with three equivalent of C5H5Na in THF,then with one equivalent of N-phenyldiethanolamine in THF-DME afforded complexes of{[(C_(5)H_(5))Ln(μ-OCH_(2)CH_(2))_(2)N(C_(6)H_(5))]4(μ_(4)-C_(l))}[Na(DME)_(4)](Ln=Sm(1),Yb(2)),being characterized by infrared spectra,elemental analyses and X-ray crystallography.They are ionic pair compounds.The anionic part is a cluster,which can be viewed as a cyclic tetramer with four(C5H5)Ln units bridged by four pairs of OR groups,forming a pinwheel structure.Both the complexes can catalyze the ring-opening polymerization ofε-caprolactone under mild conditions,and complex 1 is more active than complex 2.The polymerization accords with one order reaction kinetics for monomer concentration.The molecular weight increases with the yield increasing,and the molecular weight distribution is rather narrow(1.19<PDI<1.29).

Eco-friendly biodegradable polyurethane based coating for antibacterial and antifouling performance

Biofouling, which comprises the absorption of proteins and the adhesion of bacteria to the surface of living entities, is a severe concern for the maritime sector since it ultimately leads to hydrodynamic drag,resulting in a higher increase in fuel consumption. As a result, polymer resins are crucial in the marine sector for anti-biofouling coatings. In this work, the poly(caprolactone-ethylene glycol-caprolactone)-p olyurethane(PECL-PU) are prepared through ε-caprolactone(CL), poly(ethylene glycol)(PEG), 4,4'-methylene bis(cyclohexyl isocyanate) and 1,4 butanediol. Our study demonstrate that the PECL-PU copolymer degraded in artificial seawater(5.21%), enzymatic solution(12.63%), and seawater(13.75%)due to the presence of PEG segments in the laboratory-based test under static condition. Because the addition of PEG segments are increased the polymer's amorphous area and decreased the crystallization of the polycaprolactone(PCL) in the copolymer, as demonstrated by differential scanning calorimetry, X-ray diffraction, and water contact angle studies. Therefore, the hydrolysis rates of PECL-PU were higher than the caprolactone-co-polyurethane(CL-PU). The antifouling test showed that PECL-PU3 copolymer had about 90.29% protein resistance, 85.2% Escherichia coli(E. coli) reduction and 94.61% marine diatom Navicula incerta reduction comparison to the control. We have developed an eco-friendly and inexpensive promising degradable polyurethane for reduction of bacterial biofilm, which can preserve the formation of biofouling on marine coating under practical sea conditions.

Synthetic Absorbable Surgical Sutures

This paper reviewed all types of the polymer - based synthetic absorbable surgical sutures that have been commercially produced. The chemical component, biological and mechanical properties, and using effect of these sutures were discussed. The recent development and the possible coming research orientation in these areas were also presented.

Effect of PLA Knitted Structure on the Mechanical Properties of Composite Vascular Scaffold

A new entire biodegradable scaffold has been developed which does not require precellularization before transplantation.This new kind of vascular scaffold prototype made from porous poly-ε-caprolactone( PCL) membrane to provide three-dimensional environment for cell growth, and embedded with weft-knitted polylactic acid( PLA) fabric to support mechanics.The aim of this paper is to study the variation tendency of mechanical properties with the fabric spacing changing.The basic geometrical parameters were measured to characterize properties of the samples.The tensile and compressive elastic recovery of the samples were tested by the universal mechanical tester and radial compression apparatus,respectively.Both tensile and compressive properties enhanced when reducing the fabric spacing of the composite vascular scaffold.