Stannous Octoate Catalyst Research Articles

SYNTHESIS CO(BENZENESULFONAMIDE SERINOL-LACTIDE) FOR PREPARATION OF THE PH-SENSITIVE HYDROGEL

The pH-sensitive hydrogel based on polyurethanes is one of the most popular biodegradable copolymers that have been used in drug carrier applications. Polyurethanes containing sulfonamide groups exhibit sensitivity to changes in pH environment because they can receive and donate cationic hydrogens. In this research, the co(benzenesulfonamide serinol-lactide), named Co(BSSe-LA), was synthesized based on the ring-opening reaction of lactide and hydroxyl groups of benzenesulfonamide serinol (BSSe). The influence of reaction time and content (wt.%) of stannous octoate catalyst on the reaction efficiency of Co(BSSe-LA) was investigated. Proton nuclear magnetic resonance (H1NMR) and Fourier transform infrared spectroscopy (FTIR) analyses confirmed the successful formation of BSSe and Co(BSSe-LA). Besides, the results show that the reaction efficiency of Co(BSSe-LA) increased when the reaction time and the stannous octoate concentration increased. The reaction efficiency of Co(BSSe-LA) was 33.67 % with reaction parameters including catalyst content of 1.2 wt.%, reaction time of 24 hours and BSSe/LA molar ratio of 1/2. Co(BSSe-LA) was prepared for polymerization of polyurethane and fabrication of pH-sensitive hydrogel. Furthermore, the product can be decomposed easily in aqueous medium thanks to the ester group of lactide. This hydrogel copolymer may be potential as an injectable hydrogel for the controllable drug and protein delivery system.

Use of Novel Non-Toxic Bismuth Catalyst for the Preparation of Flexible Polyurethane Foam.

Foam products are one of the largest markets for polyurethane (PU) and are heavily used in many sectors. However, current PU formulations use highly toxic and environmentally unfriendly production processes. Meanwhile, the increasing environmental concerns and regulations are intensifying the research into green and non-toxic products. In this study, we synthesized flexible polyurethane foam (PUF) using different weight percentages (0.025%, 0.05% and 0.1%) of a non-toxic bismuth catalyst. The bismuth-catalyzed foams presented a well evolved cellular structure with an open cell morphology. The properties of the bismuth-catalyzed flexible PUF, such as the mechanical, morphological, kinetic and thermal behaviors, were optimized and compared with a conventional tin-catalyzed PUF. The bismuth-catalyst revealed a higher isocyanate conversion efficiency than the stannous octoate catalyst. When comparing samples with similar densities, the bismuth-catalyzed foams present better mechanical behavior than the tin-catalyzed sample with similar thermal stability. The high solubility of bismuth triflate in water, together with its high Lewis acidity, have been shown to benefit the production of PU foams.

Evaluation of kinetic parameters for the crystallization and degradation process of synthesized strontium mercaptosuccinate functionalized poly(ε-caprolactone) by non-isothermal approach

Strontium (Sr) mercaptosuccinate (MS) functionalized poly(e-caprolactone) (PCL) was prepared by ring opening polymerization technique in the presence of Sr-MS nanohybrid initiator and stannous octoate (SO) catalyst for 2 h at 160 °C under nitrogen atmosphere. FTIR, NMR, DSC, TGA, GPC, POM, TEM and AFM techniques were employed to characterize the Sr-MS functionalized polymer. The FTIR spectrum showed a small peak at 526 cm−1 due to the Sr–O stretching. The particle size of the Sr-MS nanohybrid functionalized PCL matrix was determined as less than 30 nm. The crystallization rate and crystallinity percentage were estimated from the non-isothermal exothermic curves. The crystallization temperature (Tc) was found to be decreased with increasing the cooling rate whereas the degradation temperature (Td) was increased with increasing the heating rate. Various kinetic models were applied to comprehend the degradation behaviour of Sr-MS functionalized PCL as well as its related kinetic parameters under non-isothermal condition. The activation energy (Ea) was calculated for both crystallization (138.5 kJ/mol) and degradation (187 kJ/mol) behaviours of Sr-MS functionalized PCL under non-isothermal condition.

Mechanistic Study of Stress Relaxation in Urethane-Containing Polymer Networks.

Cross-linked polymers are used in many commercial products and are traditionally incapable of recycling via melt reprocessing. Recently, tough and reprocessable cross-linked polymers have been realized by incorporating cross-links that undergo associative exchange reactions, such as transesterification, at elevated temperatures. Here we investigate how cross-linked polymers containing urethane linkages relax stress under similar conditions, which enables their reprocessing. Materials based on hydroxyl-terminated star-shaped poly(ethylene oxide) and poly((±)-lactide) were cross-linked with methylene diphenyldiisocyanate in the presence of stannous octoate catalyst. Polymers with lower plateau moduli exhibit faster rates of relaxation. Reactions of model urethanes suggest that exchange occurs through the tin-mediated exchange of the urethanes that does not require free hydroxyl groups. Furthermore, samples were incapable of elevated-temperature dissolution in a low-polarity solvent (1,2,4-trichlorobenzene) but readily dissolved in a high-polarity aprotic solvent (DMSO, 24 to 48 h). These findings indicate that urethane linkages, which are straightforward to incorporate, impart dynamic character to polymer networks of diverse chemical composition, likely through a urethane reversion mechanism.

Controlled Hydrolytic Degradation of Polyglycolide–Caprolactone-Based Bioabsorbable Copolymer

Polyglycolide–caprolactone (PGCL)-based copolymer was synthesized from glycolide and caprolactone by ring opening polymerization in the presence of stannous octoate catalyst and diethylene glycol initiator. The effects of prepolymerization time, monomer ratio, monomer-to-catalyst and monomer-to-initiator ratios on per cent weight conversion were optimized. The end-capped copolymer was synthesized to make absorbable sutures having controlled bioabsorbability at different pH levels. It was observed that endcapped absorbable copolymer was more stable at pH 10.0 compared to uncapped absorbable material. End-capped copolymer also retained higher tensile strength compared to uncapped copolymer after 21 days. This phenomenon of controlled hydrolytic degradation of PGCL-based bioabsorbable polymer having terminal group end-capping can be attributed to less availability of hydrophilic end groups facilitating hydrolytic degradation of polymers.

Tuning properties of poly(ethylene glycol)-block-poly(simvastatin) copolymers synthesized via triazabicyclodecene

Simvastatin was polymerized into copolymers to better control drug loading and release for therapeutic delivery. When using the conventional stannous octoate catalyst in ring-opening polymerization (ROP), reaction temperatures ≥200°C were required, which promoted uncontrollable and undesirable side reactions. Triazabicyclodecene (TBD), a highly reactive guanidine base organocatalyst, was used as an alternative to polymerize simvastatin. Polymerization was achieved at 150°C using 5kDa methyl-terminated poly(ethylene glycol) (mPEG) as the initiator. ROP reactions with 2kDa or 550Da mPEG initiators were also successful using TBD at 150°C instead of stannous octoate, which required a higher reaction temperature. Biodegradability of the poly(simvastatin) copolymer in phosphate-buffered saline was also improved, losing twice as much mass than the copolymer synthesized via stannous octoate. The three copolymers exhibited modified rates of simvastatin release, demonstrating tunability for drug delivery applications.

Optimization of Process Parameters for Controlled Ring-Opening Polymerization of Lactide to Produce Poly(L-Lactide) Diols as Precursor for Polyurethanes

ABSTRACTSeries of poly(L-Lactide) diols with molecular weights (Mn) in 2,069–4,811 g mol−1 were synthesized from L-Lactide using stannous octoate catalyst and 1,4-butanediol chain extender. Operating conditions, i.e., temperature, catalyst concentration, chain extender concentration, and reaction time, were optimized. Maximum monomer conversion and Mn were observed at 0.5 mol% SnOct2 and 1.0 mol% 1,4 butanediol (BDO) at 145°C. Poly(L-Lactide) diols were analyzed by Fourier transform infrared, proton nuclear magnetic resonance, end-group analysis, and X-ray diffraction techniques. Fourier transform infrared confirmed the formation of poly(L-Lactide) diols. Poly(L-Lactide) diols’ % degree of crystallinity was determined by X-ray diffraction. Mn was calculated by proton nuclear magnetic resonance and end-group analysis.

Study on Polyurethane Foam Insulation Materials

The foaming reaction so that all water-gel reaction and foaming reaction to reach equilibrium, the excellent thermal insulation material was prepared by the regulation of the catalyst, a nucleating agent and an isocyanate. By experiment we know that the amount of stannous octoate catalyst 6%, 4% of the amount of nucleating agent CaCO3, and the case of 100% of the amount of isocyanate, the density of the foam material and the mechanical properties of the insulation material to achieve the best value.

Synthesis, characterization and drug delivery activity of poly(anthranilicacid) based triblock copolymer

The poly(tetrahydrofuran) (PTHF) grafted poly(caprolactone)-poly(anthranilicacid)-poly(caprolactone) (PCL-PAA-PCL) co-polymer system was synthesized by using a prepolymer under nitrogen atmosphere in the presence of a stannous octoate catalyst. The [M0/I0] was maintained at 100. The polymers at each stage was characterized by various analytical techniques like FTIR spectroscopy, NMR spectroscopy, UV–visible spectroscopy, fluorescence spectroscopy, cyclic voltammetry, DSC, TGA, conductivity, FESEM, solubility test, cytotoxicity and drug release study. The results obtained here in the present investigation are critically compared with the literature values.

Synthesis, structure and properties of poly(L-lactide-co-[formula omitted]-caprolactone) statistical copolymers

Four poly(L-lactide-co-ε-caprolactone) (PLCL) copolymers were synthesized at 120, 130, 140 and 150 °C by ring opening polymerization using stannous octoate catalyst at a 2000:1 comonomer:catalyst ratio. Gel permeation chromatography (GPC) and 1H NMR measurements were performed to determine the molecular weight, composition and chain microstructure of copolymers of L-lactide(LA):ε-caprolactone(CL) synthesized using 90:10, 80:20, 75:25 and 70:30 feed ratios. The overall conversion of these PLCL copolymers was in the range of 80%–90% leading to weight average molecular weights (Mw) between 98,500 and 226,000 g mol−1 depending on feed composition and polymerization temperature. At temperatures lower than 140 °C, the incorporation of CL units into polymer chains was incomplete because of the low reactivity of CL, thus at 120 °C the copolymer composition was difficult to control obtaining more LA in the copolymer than the desired, hence the blocky character of PLCL copolymers also increased. At 150 °C the catalyst was less effective and the molecular weights of the copolymers took lower values. A temperature of 140 °C was established as optimal to obtain highest yields and molecular weight. The number average crystallizable lactide sequence lengths (lLA) shifted from 6.5 to 16.7 LA repeat units for PLCL polymerized at 140 °C while the randomness character (R) value shifted from 0.4 for polymerization at 130 °C to 0.6, at 150 °C. Increasing the LA content in the copolymers the glass transition temperature and the crystallizability and melting temperature of PLCLs approached to that of PLLA homopolymer. The aging sensitivity of PLCLs increased with CL content. A double Tg behavior due to phase separation associated to crystallizing LA blocks was observed during aging. The mechanical properties, however, evolved toward the PLLA character when the molar content of LA in PLCL was increased from 66% to 90%, observing a shift from an elastomeric thermoplastic behavior to that of a glassy plastic, reflected by an increase in tensile modulus (from 12.0 to 1343.1 MPa) and a decrease in strain recovery after break (from 93.5% to 25.0%). Small amounts of CL content in the copolymers produced large improvements in their deformability with regard to PLLA. In addition, thermogravimetric analysis demonstrated that PLCLs are more stable to thermal degradation than PLLA and they undergo a more complex degradation mechanism than those of the corresponding homopolymers.

Preparation and characterization of nanocomposites based on polylactides tethered with polyhedral oligomeric silsesquioxane

AbstractA series of polylactides tethered with polyhedral oligomeric silsesquioxane (POSS–PLAs) were synthesized via the ring‐opening polymerization of L‐lactide with 3‐hydroxypropylheptaisobutyl polyhedral oligomeric silsesquioxane (3‐hydroxypropylheptaisobutyl POSS) at a concentration of 0.02–2.00 mol % in the presence of a stannous(II) octoate catalyst.1H‐NMR spectra and a composition analysis of the POSS–PLA hybrids confirmed that 3‐hydroxypropylheptaisobutyl POSS served as an initiator for L‐lactide in the ring‐opening polymerization. X‐ray diffraction patterns evidenced that polyhedral oligomeric silsesquioxane (POSS) molecules of POSS–PLA hybrids were well dispersed without the formation of their crystalline aggregates. The POSS–PLA hybrid with 0.50 mol % POSS content was solution‐blended with a neat polylactide (PLA) homopolymer to obtain PLA/POSS–PLA nanocomposites with various POSS–PLA contents of 1–30 wt %. The X‐ray diffraction results of the PLA/POSS–PLA nanocomposites demonstrated that the POSS–PLA was well dispersed in the neat PLA matrix. The thermal and thermooxidative degradation properties of the nanocomposites were found to be improved at POSS–PLA contents of 1–20 wt %, compared to the neat PLA. The crystallization rates and crystallinities of the PLA/POSS–PLA nanocomposites were faster and higher, respectively, with increasing POSS–PLA content because of the nucleation effect of the POSS molecules in the neat PLA matrix. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Copolymerization of L-lactide and ε-caprolactone in supercritical fluid

Copolymerization of L-lactide and e-caprolactone initiated by tin (II) octoate (Sn(Oct)2) was carried out in supercritical chlorodifluoromethane (R22) with varying reaction conditions (time and temperature) and amounts of monomer and catalyst, under a pressure of 250 bar. The optimum conditions were a reaction time of 10 h and a temperature of 130 °C, which is similar to the temperature used in bulk copolymerization system. The conversion increased from 56% to 76% by increasing the reaction time from 1 to 10 h. The molecular weight also increased to 75,900 g.mol-1 over the same period, while the increased monomer concentration resulted in a high molecular weight of 86,400 g.mol-1 and a monomer conversion of 84%. Raising the reaction temperature from 90 to 130 °C increased the monomer conversion as well as the poly-L-lactide-co-e-caprolactone (PLCL) molecular weight. The variation on the stannous octoate catalyst suggested that less catalyst would decrease the caprolactone content of the polymer.

Magnetite nanoparticles stabilized with polymeric bilayer of poly(ethylene glycol) methyl ether–poly(ɛ-caprolactone) copolymers

In this work, we report a synthetic method of water dispersible magnetite nanoparticles having oleic acid and poly(ethylene glycol) methyl ether–poly(ɛ-caprolactone) (mPEG–PCL) amphiphilic block copolymer as polymeric stabilizers. The particles were prepared by coprecipitation of Fe(II) and Fe(III) in NH4OH and had bilayer surface with hydrophobic inner layer and hydrophilic corona. mPEG–PCL copolymer was synthesized by a ring-opening polymerization of ɛ-caprolactone using mPEG as a macroinitiator in the presence of stannous octoate catalyst. FTIR and thermogravimetric analysis (TGA) indicated the presence of the copolymer on the particle surface. Roles of reaction parameters, such as stabilizer concentrations and time of ultrasonicating treatment, on percent of magnetite in the complex and its magnetic properties were investigated. Transmission electron microscopy (TEM) showed the average particle size about 9.0±1.1nm in diameter. Vibrating sample magnetometry (VSM) measurement indicated that the magnetite nanoparticles were superparamagnetic at room temperature. Approximately 6.8±0.5% of indomethacin model drug (68μg/mg of magnetite) was effectively entrapped on the particles.

Branched Pentablock Poly(L-lactide-co-∊-caprolactone) Synthesis in scCO2

Pentablock poly(L-lactide-co-∊-caprolactone) (PLLA/PCL), with a central fluorinated segment and four PLLA/PCL side chains was synthesized by sequential ring-opening polymerization (ROP) with stannous octoate catalyst in an environmentally benign and clean medium, scCO2. Copolymers of PLLA and PCL are extensively researched for biomedical applications. Fluorinated hydrocarbons are similarly promising for biomedicine, and especially for oxygen-carrying substitute applications. Initially, a fluorinated reactive triblock stabilizer (prepolymer, PCL-FLKT-PCL) with inner fluorinated segment and PCL side chains was synthesized in bulk from a tetraol fluorinated alcohol (FLKT) with a 99% conversion. The prepolymer was then utilized for the synthesis of copolymers in scCO2, where PLLA segments were successively incorporated to the ends of the prepolymer, forming a pentablock structure with four polyester side chains. Reactions were carried out at 75°C and 4000-4500 psi. Solubility studies of the prepolymer and the pentablock copolymer in scCO2 showed effective solubilization at the reaction temperature and pressure. The molecular weights of the products were measured with the aid of gel permeation chromatography; the prepolymer and the copolymer possessed average number molecular weights (Mn) in the range of 13 000 and 24 000 (for 96% conversion of LLA), respectively. Low poly-dispersity indexes were obtained: 1.34 for the prepolymer and 1.08-1.34 for the pentablock copolymer. Material characterization was carried out by 1H NMR, 13C NMR, 19F NMR, differential scanning calorimetry (DSC), gel permeation chromatography (GPC) and scanning electron microscopy (SEM).

Synthesis, characterization, and in vitro degradation of star‐shaped P(ε‐caprolactone)‐b‐poly(L‐lactide)‐b‐poly(D,L‐lactide‐co‐glycolide) from hexakis [p‐(hydroxymethyl)phenoxy]cyclotriphosphazene initiator

AbstractHexaarmed star‐shaped hydroxyl‐terminated poly(ε‐caprolactone) (PCL) was successfully synthesized via the ring‐opening polymerization of ε‐caprolactone (CL) with hexakis[p‐(hydroxymethyl)phenoxy]cyclotriphosphazene initiator and stannous octoate catalyst in bulk. The star‐shaped PCL with hydroxy end groups could be used as a macroinitiator for block copolymerization with L‐lactide (L‐LA). The star‐shaped triblock copolymer was synthesized by above‐mentioned hydroxyl‐terminated star‐shaped diblock PCL‐b‐PLLA, D,L‐lactide (D,L‐LA), and glycolide (GA). IR, 1H NMR, and GPC analysis showed that the star‐shaped block copolymers were successfully synthesized and the molecular weights and the unit composition of the star‐shaped block copolymers were controlled by the molar ratios of monomer to initiator. The triblock copolymer presented a three‐phase structure, namely, PCL crystalline, PLLA crystalline, and D,L‐PLAGA amorphous domains, which made the triblock copolymer different from the diblock copolymer and star‐shaped PCL in crystallizability and thermal behaviors. Then, the in vitro degradation behaviors of the copolymers were investigated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2310–2317, 2007

Synthesis and characterization of multiblock copolymers composed of poly(5‐methyl‐5‐benzyloxycarbonyl‐1,3‐dioxan‐2‐one) outer blocks and poly(L‐lactide) inner blocks

AbstractEthylene glycol (EG) initiated, hydroxyl‐telechelic poly(L‐lactide) (PLLA) was employed as a macroinitiator in the presence of a stannous octoate catalyst in the ring‐opening polymerization of 5‐methyl‐5‐benzyloxycarbonyl‐1,3‐dioxan‐2‐one (MBC) with the goal of creating A–B–A‐type block copolymers having polycarbonate outer blocks and a polyester center block. Because of transesterification reactions involving the PLLA block, multiblock copolymers of the A–(B–A)n–B–A type were actually obtained, where A is poly(5‐methyl‐5‐benzyloxycarbonyl‐1,3‐dioxan‐2‐one), B is PLLA, and n is greater than 0. 1H and 13C NMR spectroscopy of the product copolymers yielded evidence of the multiblock structure and provided the lactide sequence length. For a PLLA macroinitiator with a number‐average molecular weight of 2500 g/mol, the product block copolymer had an n value of 0.8 and an average lactide sequence length (consecutive C6H8O4 units uninterrupted by either an EG or MBC unit) of 6.1. For a PLLA macroinitiator with a number‐average molecular weight of 14,400 g/mol, n was 18, and the average lactide sequence length was 5.0. Additional evidence of the block copolymer architecture was revealed through the retention of PLLA crystallinity as measured by differential scanning calorimetry and wide‐angle X‐ray diffraction. Multiblock copolymers with PLLA crystallinity could be achieved only with isolated PLLA macroinitiators; sequential addition of MBC to high‐conversion L‐lactide polymerizations resulted in excessive randomization, presumably because of residual L‐lactide monomer. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6817–6835, 2006

Hydrolytic degradation of poly( d, l-lactide) as a function of end group: Carboxylic acid vs. hydroxyl

d, l-Lactide was initiated with 1,4-butanediol in the presence of stannous octoate catalyst to provide hydroxyl-terminated poly( d, l-lactide) at 5000 and 20,000 g/mol. Portions of these materials were reacted with succinic anhydride in the presence of 1-methylimidazole to convert the hydroxyl functionality to succinic acid-terminated polymers in relatively high yield. The four materials were placed in a 7.4 pH buffered saline solution at 37 °C and monitored up to 180 days for their relative moisture uptake and weight loss behaviors. Carboxylic acid functionality displayed a dramatic effect on the moisture uptake behaviors for the 5000 and 20,000 g/mol polymers when compared to their respective hydroxyl functional materials. Carboxylic acid functionality significantly increased the hydrolytic degradation rate and mass loss behavior for the 5000 g/mol material, but did not affect the hydrolytic degradation rate for the higher molecular weight sample. These results suggest that moisture uptake is not the rate limiting step for the hydrolytic degradation high molecular weight poly( d, l-lactide).

Morphology and melt crystallization of poly(L-lactide) obtained by ring opening polymerization ofL-lactide with zinc catalyst

The morphology and melt crystallization of zinc catalyzed poly(L-lactide) (PLLA) were investigated by using differential scanning calorimetry (DSC), polarized optical microscopy, and scanning electron microscopy. Isothermal melt crystallization performed at 95–135°C showed that the morphology depends on the degree of supercooling, as illustrated by crystallite perfection and lamellar thickening behaviors. Double melting peak was observed on DSC thermograms and attributed to the melt-recrystallization mechanism, small and imperfect crystals becoming gradually more stable ones. Circumferential and hexagonal cracks were detected in PLLA spherulites, which were formed during melt-crystallization at 135°C and quenching in liquid nitrogen. Rhythmic growth and thermal shrinkage are suggested to be the two main factors accounting for the formation of periodic cracks. Spherulite growth rates of PLLA were evaluated by using combined isothermal and nonisothermal procedures, and were analyzed by the secondary nucleation theory. The maximum growth rate reached 9.1 μm/min at 130°C. The temperature range investigated (120–155°C) belongs to the Regime II of crystallization. The value of U* was found to be 1890 cal/mol, instead of 1500 cal/mol commonly used in literature, and Kg and σ were estimated to be 3.03 × 105 K2 and 1.537 × 10−4 J/m2, respectively. As a result, no distinct difference between PLLA catalyzed by zinc metal and those prepared with stannous octoate catalyst exists in this work. POLYM. ENG. SCI., 46:1583–1589, 2006. © 2006 Society of Plastics Engineers.

Synthesis and Characterization of Functionalizable and Photopatternable Poly(ε-caprolactone-co-RS-β-malic acid)

To create a functionalizable and photopatternable biodegradable polyester, 2-hydroylethyl methacrylate (HEMA) grafted poly(ε-caprolactone-co-RS-β-malic acid) (PCLMAc) was synthesized. The ring-opening random copolymerization of ε-caprolactone (CL) and RS-β-benzyl malolactonate (MA) using stannous octoate catalyst was systemically studied. The polymers were characterized by 1H NMR, FTIR, GPC, and DSC. The optimum copolymerization temperature was found to be 130 °C. The proportion of MA in the derived copolymers was lower than that in the feeding dose, a consequence of its lower reactivity. The molecular weight of the copolymers decreased with increasing MA content. During hydrogenolysis, the protective benzyl groups were completely replaced by carboxyl groups resulting in hydrogen bonding in the deprotected copolymers, but some degradation occurred. PCL segments in the copolymers crystallized when the MA content was lower than 16.2 mol %, and the deprotected copolymer had higher crystallinity compared to that of the corresponding protected copolymer. The glass transition temperature (Tg) of the deprotected copolymer increased greatly due to the formation of hydrogen bonds. HEMA was easily grafted on the functionalized biodegradable copolymer. The liquid HEMA grafted copolymer was shown to be suitable for UV microembossing.

Synthesis, characterization and thermal properties of hexaarmed star-shaped poly(ε-caprolactone)-b-poly(d,l-lactide-co-glycolide) initiated with hydroxyl-terminated cyclotriphosphazene

Hexakis[p-(hydroxymethyl)phenoxy]cyclotriphosphazene was prepared by the reaction of hexachlorocycltriphosphaneze with the sodium salt of 4-hydroxybenzaldehyde and subsequent reduction of aldehyde groups to alcohol groups by using sodium borohydride. Hexaarmed star-shaped hydroxyl-terminated poly(ε-caprolactone) (PCL) were successfully synthesized via ring-opening polymerization of ε-caprolactone (CL) with the above hydroxyl-terminated cyclotriphosphazene initiator and stannous octoate catalyst in bulk. The number-average molecular weight of PCL linearly increased with the molar ratio of monomer to initiator. The star-shaped PCL with hydroxy end groups could be used as a macroinitiator for block copolymerization with d,l-lactide (d,l-LA) and glycolide (GA) using stannous octoate catalyst. IR, 1H NMR and GPC analysis showed the star-block copolymers were successfully synthesized and the molecular weights and the unit composition of the star-shaped block copolymers were controlled by the molar ratios of d,l-LA and GA monomers to CL. The copolymer presented a two-phase structure, namely, PCL crystalline and d,l-LAGA amorphous domains, which made the copolymer different from linear PCL and star-shaped PCL in crystallinity and thermal behaviors.