Polycaprolactone Triblock Copolymer Research Articles

Investigating the stability of vitamin D3 and Bifidobacterium lactis nanoparticles coated with polycaprolactone-polyethylene glycol polycaprolactone triblock copolymer in Iranian white cheese and determining its physicochemical and sensory properties

Investigating the stability of vitamin D3 and Bifidobacterium lactis nanoparticles coated with polycaprolactone-polyethylene glycol polycaprolactone triblock copolymer in Iranian white cheese and determining its physicochemical and sensory properties

No Effect of Rapamycin on Cardiac Adhesion Formation: A Drug-Loaded Bioresorbable Polylactone Patch in a Porcine Cardiac Surgical Model

Background: The fusing of the epicardium and sternum due to adhesion is a common problem during repeated cardiac surgery and carries with it an increased risk of bleeding. The use of barriers and patches has been tested to prevent the formation of adhesions, but the very presence of a patch can provoke adhesion formation. The objective of this study was, therefore, to investigate both biodegradable and bioresorbable polylactone patches [(polycaprolactone-poly(ethylene oxide)-polycaprolactone tri-block copolymer (PCE)]. The patches were also tested with a controlled release of rapamycin, which prevents cell migration and extracellular matrix deposition. The clinical effectiveness of rapamycin in pericardial patches has not previously been examined. Materials and Methods: Three groups of 6 female Danish Landrace pigs underwent sternotomy and abrasion of the epicardium, before being randomized to either group 1 - the control group (with no patch), group 2 - PCE patch implanted between the sternum and epicardium, or group 3 - PCE patch and slow-release 1.6-mg rapamycin. After a median time period of 26 days, the pigs were euthanized and their hearts removed en bloc with the sternum, for macroscopic, histological and pathological examination. Results: Upon macroscopic examination, a significantly lower degree of adhesion in group 2, as compared to group 1 (p < 0.05), was found. Histological analysis of the tissues showed significantly more fibrosis, inflammation and foreign body granulomas (p < 0.05) in both group 2 and group 3, when compared to group 1. Conclusion: A PCE patch following sternotomy in animal subjects reduces postoperative macroscopic adhesions without reducing microscopic fibrosis or inflammation. Loading the patch with rapamycin was found not to increase the antifibrotic effect.

Investigation of the Water-Induced Reorganization of Polycaprolactone−Poly(fluoroalkylene oxide)−Polycaprolactone Triblock Copolymer Films by Angle-Dependent X-ray Photoelectron Spectroscopy

The water-induced reorganization of a series of poly(caprolactone)−poly(fluoroalkylene oxide)−poly(caprolactone) (PCL−PFPE−PCL) thin film surfaces was studied by angle-dependent X-ray photoelectron spectroscopy (XPS). The reorganization was studied as a function of polymer chain length, water exposure time, and XPS sampling depth. The prepared films were exposed to water and then frozen in liquid nitrogen to preserve the surface composition during XPS analysis. The XPS results showed the PFPE block segment length influenced the extent and rate of segment reorganization at the surface. The detected changes were shown to be reversible upon re-exposure to air and the effect of liquid-nitrogen freezing was determined to be negligible.

Oxygen permeability of biodegradable copolycaprolactones

Polycaprolactone is one of the biodegradable polymers with good drug permeability. In the present paper, polycaprolactone and three kinds of copolycaprolactone–polycaprolactone–poly(ethylene oxide)– polycaprolactone triblock copolymer (PCE), polycaprolactone/polycaprolactone-poly(ethylene oxide)/polylactide tricomponents random block copolymer (PCEL) and polycaprolactone/poly(ethylene terephthalate) random block copolymer (PETCL)– were synthesized. The biodegradation behavior of these polymers were shown by degradation tests in vitro, ex vivo and in vivo. The oxygen permeabilities of these polymers were in the range of 10−10 ∼ 10−9 cm3 (STP) cm/cm2 sec cm Hg. Copolymers PCE and PCEL displayed O2 and N2 permeability coefficients (PO2/PN2) ratios of about 9. The effects of composition and crystallinity of the copolymers on biodegradability and the oxygen permeability of the polymer were discussed. Copyright © 1999 John Wiley & Sons, Ltd.

Blends of polycaprolactone-poly(dimethylsiloxane)-polycaprolactone triblock copolymer with poly(vinyl chloride): preparation and characterization

Miscibility, thermal, mechanical, gas permeation, morphological and surface properties of poly(vinyl chloride) (PVC) blends containing 1–10% triblock polycaprolactone—poly(dimethylsiloxane)—polycaprolactone (PCL-PDMS-PCL) copolymer were investigated by using several techniques. Fourier transform infra-red analysis of blends reveal the existence of specific interactions via hydrogen bonding between the α-hydrogen of PVC and the carbonyl group of PCL in the triblock copolymer. This PCL-PDMS-PCL/PVC blend system exhibited a single glass transition according to differential scanning calorimetry and dynamic mechanical thermal analysis results. Stress—strain results showed that PCL-PDMS-PCL triblock copolymer is a very effective plasticizer for PVC. Gas permeability of the blends increased with the copolymer content. Morphological and surface properties of the blend system were examined by scanning electron microscopy and contact angle measurements.

Modification of polycyanurate networks with protic additives based on polydimethylsiloxane

AbstractHydroxy telechelic polycaprolactone / polydimethylsiloxane / polycaprolactone triblock copolymers were used to modify aromatic polycyanurate networks through a polycondensation‐induced phase separation. Model studies revealed that the cyclotrimerization mechanism in the presence of alcohol functions was complex. The additives, which activate the reaction, are finally chemically linked to the matrix. Both thermodynamic and kinetic features result in very finely divided morphologies, with highly interpenetrated phases which contribute to a great improve of the static mechanical properties.

Morphology and properties of polycaprolactone‐poly(dimethyl siloxane)‐polycaprolactone triblock copolymers

AbstractThe molecular structure, crystallization, solid‐state morphology, thermal properties, and phase behavior of two copolymers consisting of a poly(dimethylsiloxane) (PDMS) mid‐block coupled to polycaprolactone (PCL) end‐blocks were investigated. Both copolymers (which differ only in the molecular lengths of the PCL end‐blocks) were found to be lamellar systems, whose core consists of PCL chains having the same crystal structure as PCL homopolymer, and whose amorphous interlayers contain the PDMS blocks and the PCL noncrystalline segments. From x‐ray and electron‐microscopy results, it is expected that the PCL blocks may be folded once in the longer copolymer and not at all in the shorter. As a result of their differing PCL lengths, the former crystallizes as regular PCL spherulites (at a growth rate reduced with respect to PCL homopolymer), whereas the latter yields only defective, immature axialites of low overall crystallinity. Electron diffraction showed that these spherulites grow preferentially along b crystallographic axis and that the PCL crystalline stems are arranged perpendicularly to their lamellae. © 1993 John Wiley &amp; Sons, Inc.