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A novel semi-crystalline polyhydroxyether, poly(hydroxyether ketone) (PHEK), was synthesized via the direct polycondensation between 4,4-dihydroxybenzophenone and epichlorohydrin. By means of Fourier transform infrared and NMR spectroscopy and gel permeation chromatography (GPC), the structure of PHEK was characterized. Differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXRD) show that PHEK is a semi-crystalline polymer with a high rate of crystallization. The polymer possesses a glass transition temperature of 109 °C and a melting temperature of 239 °C. When 4,4′-isopropylidenediphenol was used as a second bisphenol and was added to copolymerize with a stoichiometric amount of epichlorohydin, a series of polyhydroxyether copolymers were obtained. The copolymers with various compositions were characterized by means of NMR, GPC, WAXRD and DSC. It was found that the crystallinity of the copolymers dramatically decreased with increasing content of 4,4′-isopropylidenediphenol. The glass transition temperatures of the copolymers are intermediate between those of PHEK and the poly(hydroxyether of bisphenol A) and decreased with increasing content of 4,4′-isopropylidenediphenol. Copyright © 2007 Society of Chemical Industry

Dendritic star-shaped poly(ε-caprolactone)-block-poly(L-lactide) (PCL-b-PLLA) diblock copolymers were synthesized via sequential ring-opening polymerization. In the first step, an aliphatic dendritic polyester containing 16 terminal hydroxyl groups was used as the core molecule to initiate the ring-opening polymerization of ε-caprolactone, which was catalyzed by stannous(II) octanoate, to obtain dendritic star-shaped poly(ε-caprolactone) (PCL) terminated with hydroxyls, which was used further to initiate the ring-opening polymerization of L-lactide to form the dendritic star-shaped diblock copolymers. The dendritic star-shaped polymers (PCL-b-PLLA) were characterized with nuclear magnetic resonance spectroscopy and gel permeation chromatography. The results showed that the arm length of the dendritic star-shaped polymers could be well controlled in terms of the molar ratios of the initiators (i.e., the aliphatic dendritic polyester and star-shaped PCL) to the monomers (i.e., ε-caprolactone and L-lactide). The crystalline structure and thermal properties of the dendritic star-shaped polymers were investigated with X-ray diffraction and differential scanning calorimetry. The X-ray diffraction indicated that the formation of the dendritic star-shaped topological structure did not affect the structure of the crystals of PCL and poly(L-lactide) (PLLA) blocks. The thermal analyses showed that the crystallization rate of the PCL blocks in the block copolymers was greatly reduced compared to that in the parent dendritic star-shaped PCL. This observation could be attributed to the confinement of the dendritic core and PLLA blocks upon the crystallization of the PCL blocks. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007

In this study, we investigated the melting and crystallization behavior of polyhedral oligomeric silsesquioxane (POSS)-capped poly(ε-caprolactone) PCL with various lengths of PCL chains by means of X-ray diffraction and differential scanning calorimetry. This organic–inorganic macromolecule possesses a tadpole-like structure in which the bulky POSS cage is the “head” whereas PCL chain the “tail”. The novel organic–inorganic association result in the significant alterations in the melting and crystallization behavior of PCL. The POSS-terminated PCL displayed the enhanced equilibrium melting points compared to the control PCL. Both the overall crystallization rate and the spherulitic growth rate of the POSS-terminated PCLs increased with increasing the concentration of POSS (or with decreasing length of PCL chain in the hybrids). The analysis of Avrami equation shows that the crystallization of the POSS-terminated PCL preferentially followed the mechanism of spherulitic growth with instantaneous nuclei. It is found that the folding free energy of surface for the POSS-terminated PCLs decreased with increasing the concentration of POSS. It is found that the folding free energy of surface for the POSS-terminated PCLs decreased with increasing the concentration of POSS. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2201–2214, 2007

A tetraarmed star-shaped poly(methyl methacrylate) (s-PMMA) was synthesized via atom transfer radical polymerization with 2-bromoisobutyryl pentaerythritol as the initiator. For comparison, a linear PMMA with the identical molecular weight (l-PMMA) was also prepared. The blends of the two PMMA samples with poly (vinylidene fluoride) (PVDF) were prepared to investigate the effect of macromolecular topological structure on miscibility and crystallization behavior of the binary blends. The behavior of single and composition-dependent glass transition temperatures was found for the blends of s-PMMA with PVDF, indicating that the s-PMMA is miscible with PVDF in the amorphous state just like l-PMMA. The miscibility was further evidenced by the depression of equilibrium melting points. It is found that the blends of s-PMMA and PVDF displayed the larger k value of Gordon–Taylor equation than the blends of l-PMMA and PVDF blends. According to the depression of equilibrium melting points, the intermolecular parameters for the two blends were estimated. It is noted that the s-PMMA/PVDF blends displayed the lower interaction parameter than l-PMMA/PVDF blends. The isothermal crystallization kinetics shows that the crystallization of PVDF in the blends containing s-PMMA is faster than that in the blends containing the linear PMMA. The surface-folding free energy of PVDF chains in the blends containing s-PMMA is significantly lower than those in the blends containing l-PMMA. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2580–2593, 2007

Supramolecular inclusion complexes (ICs) involving polyhedral oligomeric silsesquioxane (POSS) capped poly(ϵ-caprolactone) (PCL) and α-cyclodextrin (α-CD) were investigated. POSS-terminated PCLs with various molecular weights were prepared via the ring-opening polymerization of ϵ-caprolactone (CL) with 3-hydroxypropylheptaphenyl POSS as an initiator. Because of the presence of the bulky silsesquioxane terminal group, the inclusion complexation between α-CD and the POSS-capped PCL was carried out only with a single end of a PCL chain threading inside the cavity of α-CD, which allowed the evaluation of the effect of the POSS terminal groups on the efficiency of the inclusion complexation. The X-ray diffraction results indicated that the organic–inorganic ICs had a channel-type crystalline structure. The stoichiometry of the organic–inorganic ICs was quite dependent on the molecular weights of the POSS-capped PCLs. With moderate molecular weights of the POSS-capped PCLs (e.g., M_n =3860 or 9880), the stoichiometry was 1:1 mol/mol (CL unit/α-CD), which was close to the literature value based on the inclusion complexation of α-CD with normal linear PCL chains with comparable molecular weights. When the PCL chains were shorter (e.g., for the POSS-capped PCL of M_n = 1720 or 2490), the efficiency of the inclusion complexation decreased. The decreased efficiency of the inclusion complexation could be attributed to the lower mobility of the bulky POSS group, which restricted the motion of the PCL chain attached to the silsesquioxane cage. This effect was pronounced with the decreasing length of the PCL chains. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1247–1259, 2007

Templated synthesis of poly(cyclotriphosphaze-co-4,4′-sulfonyldiphenol) nanotubes (see figure) via a one-pot approach was achieved by the in situ formation of triethylammonium chloride nanocrystals during the polymerization. The triethylammonium chloride templates can eventually be removed by washing with water. The dimensions of the nanotubes can be controlled by modification of the experimental conditions.

Benzoxazine bearing trimethoxylsilane (BA-b) was successfully synthesized via Mannich condensation among phenol, paraformaldehyde, and γ-aminopropyltrimethoxysilane. The hydrolysis and condensation of the BA-b catalyzed by hydrochloric acid can afford a soluble polysilsesquioxane bearing benzoxazine groups (denoted PSSQ-b). By initiating the cocuring reaction of PSSQ-b with difunctional benzoxazine of bisphenol A (BA-a), the inorganic–organic hybrids of polybenzoxazine with polysilsesquioxane were prepared. The hybrids displayed enhanced T_g's in comparison with the control polybenzoxazine. In terms of initial decomposition temperature (T_d) and char and ceramic yields, the hybrids exhibited improved thermal stability as shown by thermogravimetric analysis (TGA). © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 927–936, 2006

Summary: OpePOSS was incorporated into polyurethane to make organic-inorganic hybrid composites and nano-composites containing up to 20 wt.-% POSS were prepared. The formation of the hybrid polyurethane networks is ascribed to two principal cross-linking reactions: i) the cross-linking reaction between MOCA and the polyurethane prepolymer and ii) the inter-component reaction between the PU networks and OpePOSS. The latter was confirmed by model compound reactions. TEM indicates that the POSS was homogeneously dispersed in the polymer matrix at the nanometer scale. DSC showed that the nanocomposites displayed increased glass transition temperatures compared to the control polyurethane. In terms of TGA, the nanocomposites displayed improved thermal stability. Tensile tests indicate that the organic-inorganic hybrid networks were significantly reinforced with the inclusion of POSS. Contact angle measurements show that the organic-inorganic nanocomposites displayed a significant enhancement in surface hydrophobicity as well as a reduction in the surface free energy. The improvement in surface properties was ascribed to the presence of the POSS moiety in place of the polar component of polyurethane. XPS shows enrichment with Si-containing moieties on the surfaces.

The comparative studies on the miscibility and phase behavior between the blends of linear and star-shaped poly(2-methyl-2-oxazoline) with poly(vinylidene fluoride) (PVDF) were carried out in this work. The linear poly(2-methyl-2-oxazoline) was synthesized by the ring opening polymerization of 2-methyl-2-oxazoline in the presence of methyl p-toluenesulfonate (MeOTs) whereas the star-shaped poly(2-methyl-2-oxazoline) was synthesized with octa(3-iodopropyl) polyhedral oligomeric silsesquioxane [(IC₃H₆)₈Si₈O₁₂, OipPOSS] as an octafunctional initiator. The polymers with different topological structures were characterized by means of Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. It is found that the star-shaped poly(2-methyl-2-oxazoline) was miscible with poly(vinylidene fluoride) (PVDF), which was evidenced by single glass-transition temperature behavior and the equilibrium melting-point depression. Nonetheless, the blends of linear poly(2-methyl-2-oxazoline) with PVDF were phase-separated. The difference in miscibility was ascribed to the topological effect of PMOx macromolecules on the miscibility. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 942–952, 2006

The miscibility of poly(hydroxyether terephthalate ester) (PHETE) with poly(4-vinyl pyridine) (P4VP) was established on the basis of thermal analysis. Differential scanning calorimetry showed that each blend displayed a single glass-transition temperature (T_g), which is intermediate between those of the pure polymers and varies with the composition of blend. The T_g-composition relationship can be well described with Kwei equation with k = 1 and q = −30.8 (K), suggesting the presence of the intermolecular specific interactions in the blend system. To investigate the intermolecular specific interactions in the blends, the model compounds such as 1,3-diphenoxy-2-propanol, 4-methyl pyridine, and ethyl benzoate were used to determine the equilibrium constants, according to Coleman and Painter model, to account for the association equilibriums of several structural moieties, using liquid Fourier transform infrared difference spectroscopy. In terms of the difference in the association equilibrium constant, it is proposed that there are the competitive specific interactions in the blends, which were confirmed by means of Fourier transform infrared spectroscopy of the blends. It is observed that upon adding P4VP to the system, the ester carbonyls of PHETE that were H-bonded with the hydroxyl groups were released because of the formation of the stronger interchain association via the hydrogen bonding between the hydroxyls of PHETE and tertiary nitrogen atoms of P4VP. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1618–1626, 2006

Polyphenylsilsesquioxane (PPSQ) was incorporated into an epoxy resin to prepare organic–inorganic composites, and two strategies were adopted to afford composites with different morphologies. Phase separation induced by polymerization occurred in the physical blending system. However, nanostructured composites were obtained when a catalytic amount of aluminum triacetylacetonate was added to mediate the reaction between PPSQ and diglycidyl ether of bisphenol A (DGEBA). The intercomponent reaction significantly suppressed the phase separation on the micrometer scale. Organic–inorganic composites with different morphologies displayed quite different thermomechanical properties. Both differential scanning calorimetry and dynamic mechanical analysis showed that the nanostructured composites possessed higher glass-transition temperatures than the phase-separated composites with the same loading of PPSQ, although the intercomponent reaction between PPSQ and DGEBA reduced the crosslinking density of the epoxy matrix. This result was ascribed to the presence of nanosized PPSQ domains in the nanostructured composites, which acted as physical crosslinking sites and thus reinforced the epoxy networks. The nanoreinforcement of the PPSQ domains afforded the enhanced dynamic storage modulus for the nanostructured composites in comparison with the phase-separated composites with a PPSQ concentration less than 15 wt %. In terms of thermogravimetric analysis, the organic–inorganic composites displayed improved thermal stability and flame retardancy. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1093–1105, 2006

Summary: Octaaminophenyl polyhedral oligomeric silsesquioxane (OapPOSS) was used as a crosslinking agent together with 4,4^′-methylenebis-(2-chloroaniline) to prepare polyurethane networks containing POSS. Fourier transform infrared spectroscopy (FT-IR), dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) were employed to characterize the POSS-reinforced polyurethane. The POSS-containing PU networks displayed enhanced glass transition temperatures (T_gs) and the storage moduli of the networks of the glassy state and rubber plateaus were also observed to be significantly higher than that of the control polyurethane although only a small amount of POSS was incorporated into the systems. The results can be ascribed to the significant nanoscale reinforcement effect of POSS cages on the polyurethane matrix. TGA results showed the thermal stability was also improved with incorporation of POSS into the system.

Summary: Octa(propylglycidyl ether) polyhedral oligomeric silsesquioxane (OpePOSS) was used as the crosslinking agent to prepare the nanocrosslinked poly(4-vinylpyridine) (P4VP) with POSS content up to 55.2 wt.-%. The formation of the crosslinked structure is ascribed to the macromolecular reaction between pyridine rings of P4VP and epoxide groups of OpePOSS. The POSS-crosslinked P4VP displayed enhanced glass transition temperatures (T_gs) and an improved thermal stability in terms of the results of thermal analysis.

Summary: The ternary thermosetting blends composed of epoxy resin, poly(ethylene oxide) (PEO) and poly(ε-caprolactone) (PCL) were prepared via in situ polymerization of epoxy monomers in the presence of the two crystalline polymers, PEO and PCL. DSC results showed that the binary blends of epoxy with PEO (and/or PCL) are fully miscible in the entire composition in the amorphous state. FTIR indicates that there were interchain specific interactions between the crosslinked epoxy and the linear polymers in the binary blends and the hydrogen bonding interactions between epoxy and PCL are much weaker than those between epoxy and PEO. The difference in the strength of interchain specific interactions gives rise to the competitive hydrogen bonding interactions in the ternary blends of epoxy, PEO and PCL, which were evidenced by the results of FTIR. The results of optical microscopy and DSC showed that in the ternary blends PCL component separated out with inclusion of PEO. The formation of the specific phase structures is ascribed to the competitive interchain specific interactions among the crosslinked epoxy, PEO and PCL.

Summary: Octamaleimidophenyl polyhedral oligomeric silsesquioxane (OmipPOSS) was synthesized via the imidization reaction between octaaminophenyl polyhedral oligomeric silsesquioxane (OapPOSS) and maleic anhydride, and it was characterized by means of Fourier transform infrared (FTIR) and NMR spectroscopies. OmipPOSS was further employed to prepare epoxy hybrids. The thermosetting hybrids containing OmipPOSS up to 10 wt.-% were obtained via in situ polymerization of diglycidyl ether of bisphenol A (DGEBA) and 4,4′-diaminodiphenylmethane (DDM) in the presence of OmipPOSS. High-resolution transmission electronic microscopy (TEM) indicates that the nanometer-scaled dispersion of POSS molecules was obtained, suggesting that the nanocomposites were successfully prepared. The results of DSC showed that the glass transition temperatures (T_g's) of the POSS-containing nanocomposites are dependent on the content of POSS in the nanocomposites. When the contents of POSS are less than 5 wt.-%, the nanocomposites displayed the enhanced glass transition temperatures (T_g's) in comparison with control epoxy. Thermogravimetric analysis (TGA) showed that all the nanocomposites containing POSS displayed improved char yield, suggesting the flame retardance of the materials is improved.

Thermosetting blends composed of phloroglucinol-cured bisphenol S epoxy resin and poly(ethylene oxide) (PEO) were prepared via the in situ curing reaction of epoxy in the presence of PEO, which started from initially homogeneous mixtures of diglycidyl ether of bisphenol S, phloroglucinol, and PEO. The miscibility of the blends after and before the curing reaction was established on the basis of thermal analysis (differential scanning calorimetry). Single and composition-dependent glass-transition temperatures (T_g's) were observed for all the blend compositions after and before curing. The experimental T_g's could be explained well by the Gordon–Taylor equation. Fourier transform infrared spectroscopy indicated that there were competitive hydrogen-bonding interactions in the binary thermosetting blends upon the addition of PEO to the system, which was involved with the intramolecular and intermolecular hydrogen-bonding interactions, that is, OH···OS, OH···OH, and OH, versus ether oxygen atoms of PEO between crosslinked epoxy and PEO. On the basis of infrared spectroscopy results, it was judged that from weak to strong the strength of the hydrogen-bonding interactions was in the following order: OH···OS, OH···OH, and OH versus ether oxygen atoms of PEO. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 359–367, 2005

Summary: Polybenzoxazine (PBA-a)/poly(ε-caprolactone) (PCL) blends were prepared by an in situ curing reaction of benzoxazine (BA-a) in the presence of PCL. Before curing, the benzoxazine (BA-a)/PCL blends are miscible, which was evidenced by the behaviors of single and composition-dependant glass transition temperature and equilibrium melting point depression. However, the phase separation induced by polymerization was observed after curing at elevated temperature. It was expected that after curing, the PBA-a/PCL blends would be miscible since the phenolic hydroxyls in the PBA-a molecular backbone have the potential to form intermolecular hydrogen-bonding interactions with the carbonyls of PCL and thus would fulfil the miscibility of the blends. The resulting morphology of the blends prompted an investigation of the status of association between PBA-a and PCL under the curing conditions. Although Fourier-transform infrared spectroscopy (FT-IR) showed that there were intermolecular hydrogen-bonding interactions between PBA-a and PCL at room temperature, especially for the PCL-rich blends, the results of variable temperature FT-IR spectroscopy by the model compound indicate that the phenolic hydroxyl groups could not form efficient intermolecular hydrogen-bonding interactions at elevated temperatures, i.e., the phenolic hydroxyl groups existed mainly in the non-associated form in the system during curing. The results are valuable to understand the effect of curing temperature on the resulting morphology of the thermosetting blends.

Summary: The blends of poly(hydroxyether sulfone) (PHES) with poly(N-vinylpyrrolidone) (PVPy) were investigated by means of differential scanning calorimetry (DSC) and FTIR spectroscopy. The miscibility of the blend system was established on the basis of the thermal analysis results. DSC showed that the PHES/PVPy blends prepared by casting from N,N-dimethylformamide (DMF) possessed single, composition-dependent glass transition temperatures, indicating that the blends are miscible in the entire composition. The experimental glass transition temperatures have higher values than those calculated on the basis of additive behavior; the variation of the glass transition temperatures of the blends was accounted for by the Kwei equation. FTIR studies indicate that competitive hydrogen bonding interactions exist upon addition of PVPy to the system, which were involved in the self- and cross-association, i.e., OH···OS, OH···OH of PHES and OH···OC< of PVPy. The FTIR spectra in the range of the sulfonyl stretching vibrations showed that the hydroxyl-associated sulfonyl groups are partially “set free” upon addition of PVPy to the system. The IR spectroscopic investigation of both the model compounds and the PHES/PVPy blends suggests that the strength of the hydrogen bonding interactions in the blend system increases in the following order: OH···OS, OH···OH and OH···OC<.

The poly(sily ether) with pendant chloromethyl groups (PSE) was synthesized by the polyaddition of dichloromethylsilane (DCM) and diglycidylether of bisphenol A (DGEBA) with tetrabutylammonium chloride (TBAC) as a catalyst. This polymer was miscible with diglycidyl ether of bisphenol A (DGEBA), the precursor of epoxy resin. The miscibility is considered to be due mainly to entropy contribution because the molecular weight of DGEBA is quite low. The blends of epoxy resin with PSE were prepared through in situ curing reaction of diglycidyl ether of bisphenol A (DGEBA) and 4,4′-diaminodiphenylmethane (DDM) in the presence of PSE. The DDM-cured epoxy resin/PSE blends with PSE content up to 40 wt % were obtained. The reaction started from the initial homogeneous ternary mixture of DGEBA/DDM/PSE. With curing proceeding, phase separation induced by polymerization occurred. PSE was immiscible with the 4,4′-diaminodiphenylmethane-cured epoxy resin (ER) because the blends exhibited two separate glass transition temperatures (T_gs) as revealed by the means of differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). SEM showed that all the ER/PSE blends are heterogeneous. Depending on blend composition, the blends can display PSE- or epoxy-dispersed morphologies, respectively. The mechanical test showed that the DDM-cured ER/PSE blend containing 25 wt % PSE displayed a substantial improvement in Izod impact strength, i.e., epoxy resin was significantly toughened. The improvement in impact toughness corresponded to the formation of PSE-dispersed phase structure. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 505–512, 2003

Poly(hydroxyether of phenolphthalein) (PPH) was synthesized through the polycondensation of phenolphthalein with epichlorohydrin. It was characterized by Fourier transform infrared (FTIR) spectroscopy, NMR spectroscopy, and differential scanning calorimetry (DSC). The miscibility of the blends of PPH with poly(ethylene oxide) (PEO) was established on the basis of the thermal analysis results. DSC showed that the PPH/PEO blends prepared via casting from N,N-dimethylformamide possessed single, composition-dependent glass-transition temperatures. Therefore, the blends were miscible in the amorphous state for all compositions. FTIR studies indicated that there were competitive hydrogen-bonding interactions with the addition of PEO to the system, which were involved with OH…OC〈, OH…OH, and OH vs ether oxygen atoms of PEO hydrogen bonding, that is both intramolecular and intermolecular, between PPH and PEO). Some of the hydroxyl stretching vibration bands significantly shifted to higher frequencies, whereas others shifted to lower frequencies, and this suggested the formation of hydrogen bonds between the pendant hydroxyls of PPH and ether oxygen atoms of PEO, which were stronger than the intramolecular hydrogen bonding between hydroxyls and carbonyls of PPH. The FTIR spectra in the range of carbonyl stretching vibrations showed that the hydroxyl-associated carbonyl groups were partially set free because of the presence of the competitive hydrogen-bonding interactions. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 466–475, 2003

Crystalline thermosetting blends composed of 2,2′-bis[4-(4-aminophenoxy)phenyl]propane-crosslinked epoxy resin (ER) and poly(ϵ-caprolactone) (PCL) were investigated by means of Fourier transform infrared (FTIR) spectroscopy and high-resolution solid-state NMR spectroscopy. FTIR investigations indicated that there were specific intermolecular interactions between ER and PCL and that the intermolecular hydrogen-bonding interactions were weaker than the self-association in pure epoxy. The intermolecular hydrogen bonding was considered to be the driving force for the miscibility of the thermosetting blends. For the examination of the miscibility of the thermosetting blends at the molecular level, high-resolution solid-state ¹³C cross-polarity/magic-angle spinning (CP-MAS) NMR spectroscopy was employed. The line width of ¹³C CP-MAS spectra decreased with increasing PCL contents, and the chemical shift of the carbonyl carbon resonance of PCL shifted to a low field with an increasing epoxy content in the blends. The proton spin–lattice relaxation experiments in the laboratory frame showed that all the blends possessed identical, composition-dependent relaxation times (i.e., the proton spin–lattice relaxation times in the laboratory frame), suggesting that the thermosetting blends were homogeneous on the scale of 20–30 nm in terms of the spin-diffusion mechanism, and this was in a good agreement with the results of differential scanning calorimetry and dynamic mechanical analysis. For the examination of the miscibility of the blends at the molecular level, the behavior of the proton lattice relaxation in the rotating frame was investigated. The homogeneity of the thermosetting blends at the molecular level was quite dependent on the blend composition. The PCL-lean ER/PCL blends (e.g., 70/30) displayed a single homogeneous amorphous phase, and the molecular chains were intimately mixed on the segmental scale. The PCL-rich blends displayed biexponential decay in experiments concerning the proton spin–lattice relaxation times in the rotating frame, which was ascribed to amorphous and crystalline phases. In the amorphous region, the molecular chains of epoxy and PCL were intimately mixed at the molecular level. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1099–1111, 2003

Crystalline thermosetting blends composed of 2,2′-bis[4-(4-aminophenoxy)phenyl]propane (BAPP)-cured epoxy resin (ER) and poly(ϵ-caprolactone) (PCL) were prepared via the in situ curing reaction of epoxy monomers in the presence of PCL, which started from initially homogeneous mixtures of diglycidyl ether of bisphenol A (DGEBA), BAPP, and PCL. The miscibility of the blends after and before the curing reaction was established with differential scanning calorimetry and dynamic mechanical analysis. Single and composition-dependent glass-transition temperatures (T_g's) were observed in the entire blend composition after and before the crosslinking reaction. The experimental T_g's were in good agreement with the prediction by the Fox and Gordon–Taylor equations. The curing reaction caused a considerable increase in the overall crystallization rate and dramatically influenced the mechanism of nucleation and the growth of the PCL crystals. The equilibrium melting point depression was observed for the blends. An analysis of the kinetic data according to the Hoffman–Lauritzen crystallization kinetic theory showed that with an increasing amorphous content, the surface energy of the extremity surfaces increased dramatically for DGEBA/PCL blends but decreased for ER/PCL blends. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1085–1098, 2003