Preparation of honeycomb films from nitryl poly(ether ether ketone)s via water‐droplet templating

The fabrication of honeycomb‐patterned films from nitryl poly(ether ether ketone)s (PEEK‐NO₂) in a high‐humidity atmosphere was reported in this article. PEEK‐NO₂ was prepared through acid (nitric acid and sulfuric acid) nitration from poly(ether ether ketone)s (PEEK). The obtained polymer, which was characterized by Fourier transform infrared (FT‐IR), X‐ray diffraction (XRD), and differential scanning calorimetry (DSC) showed excellent solubility and thermal stability. Some influence factors on the pattern formation and the fabrication of the porous structure, such as the solution concentration, the solvent, and the atmosphere humidity, were investigated. The results showed that with the increase of the solution concentration, the aperture of the film diminished gradually; the lower the solvents´ boiling point were, the smaller the films´ apertures were and the more regular the pores´ arrange; only under high‐humidity circumstances could obvious and ordered honeycomb films be formed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Water‐assisted formation of honeycomb films of poly(L‐lactic‐co‐glycolic acid)

The ordered honeycomb structures of poly(L ‐lactic‐co‐glycolic acid) and poly(D ,L ‐lactic‐co‐glycolic acid) fabricated in a humid atmosphere were reported in this paper. It was found that surfactants were important in the formation of honeycomb films of hydrophobic polymer. The affecting factors, such as the environment temperature, the atmosphere humidity, and the concentration of the polymer solution of the honeycomb porous structure, were also tested. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1013–1018, 2006     

Preparation of electrorheological active ionomers from poly(2‐hydroxyethyl methacrylate)‐co‐poly(4‐vinyl pyridine)

In this study, synthesis, characterization, partial hydrolysis, and salt formation of poly(2‐hydroxyethyl methacrylate)‐co‐poly(4‐vinyl pyridine), (poly(HEMA)‐co‐poly‐(4‐VP)) copolymers were investigated. The copolymers were synthesized by free radical polymerization using K₂S₂O₈ as an initiator. By varying the monomer/initiator ratio, chain lengths of the copolymers were changed. The copolymers were characterized by gel permeation chromatography (GPC), viscosity measurements, ¹H and ¹³C NMR and FTIR spectroscopies, elemental analysis, and end group analysis methods. The copolymers were partially hydrolyzed by p‐toluene sulfonic acid monohydrate (PTSA·H₂O) and washed with LiOH_(aq) solution to prepare electrorheological (ER) active ionomers, poly(Li‐HEMA)‐co‐poly(4‐VP). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3540–3548, 2006     

Porous biodegradable polyester blends of poly(L‐lactic acid) and poly(ε‐caprolactone): physical properties,morphology, and biodegradation

Poly(L ‐lactic acid) (PLLA), poly(ε‐caprolactone) (PCL), and their films without or blended with 50 wt% poly(ethylene glycol) (PEG) were prepared by solution casting. Porous films were obtained by water‐extraction of PEG from solution‐cast phase‐separated PLLA‐blend‐PCL‐blend‐PEG films. The effects of PLLA/PCL ratio on the morphology of the porous films and the effects of PLLA/PCL ratio and pores on the physical properties and biodegradability of the films were investigated. The pore size of the blend films decreased with increasing PLLA/PCL ratio. Polymer blending and pore formation gave biodegradable PLLA‐blend‐PCL materials with a wide variety of tensile properties with Young's modulus in the range of 0.07–1.4 GPa and elongation at break in the range 3–380%. Pore formation markedly increased the PLLA crystallinity of porous films, except for low PLLA/PCL ratio. Polymer blending as well as pore formation enhanced the enzymatic degradation of biodegradable polyester blends. Copyright © 2006 Society of Chemical Industry     

Part 7. Effects of poly(L‐lactide‐co‐ϵ‐caprolactone) on morphology,structure, crystallization,and physical properties of blends of poly(L‐lactide) and poly(ϵ‐caprolactone)

Blended films of poly(L ‐lactide) [ie poly(L ‐lactic acid)] (PLLA) and poly(?‐caprolactone) (PCL) without or mixed with 10 wt% poly(L ‐lactide‐co‐?‐caprolactone) (PLLA‐CL) were prepared by solution‐casting. The effects of PLLA‐CL on the morphology, phase structure, crystallization, and mechanical properties of films have been investigated using polarization optical microscopy, scanning electron microscopy, differential scanning calorimetry and tensile testing. Addition of PLLA‐CL decreased number densities of spherulites in PLLA and PCL films, and improved the observability of spherulites and the smoothness of cross‐section of the PLLA/PCL blend film. The melting temperatures (T_m) of PLLA and PCL in the films remained unchanged upon addition of PLLA‐CL, while the crystallinities of PLLA and PCL increased at PLLA contents [X_PLLA = weight of PLLA/(weight of PLLA and PCL)] of 0.4–0.7 and at most of the X_PLLA values, respectively. The addition of PLLA‐CL improved the tensile strength and the Young modulus of the films at X_PLLA of 0.5–0.8 and of 0–0.1 and 0.5–0.8, respectively, and the elongation at break of the films at all the X_PLLA values. These findings strongly suggest that PLLA‐CL was miscible with PLLA and PCL, and that the dissolved PLLA‐CL in PLLA‐rich and PCL‐rich phases increased the compatibility between these two phases. © 2003 Society of Chemical Industry     

Synthesis and characterization of a poly(ether–ester) copolymer from poly(2,6 dimethyl‐1,4‐phenylene oxide) and poly(ethylene terephthalate)

A series of poly(ether–ester) copolymers were synthesized from poly(2,6 dimethyl‐1,4‐phenylene oxide) (PPO) and poly(ethylene terephthalate) (PET). The synthesis was carried out by two‐step solution polymerization process. PET oligomers were synthesized via glycolysis and subsequently used in the copolymerization reaction. FTIR spectroscopy analysis shows the coexistence of spectral contributions of PPO and PET on the spectra of their ether–ester copolymers. The composition of the poly(ether–ester)s was calculated via ¹H NMR spectroscopy. A single glass transition temperature was detected for all synthesized poly(ether–ester)s. T_g behavior as a function of poly(ether–ester) composition is well represented by the Gordon‐Taylor equation. The molar masses of the copolymers synthesized were calculated by viscosimetry. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Synthesis of poly(vinyl alcohol)‐graft‐poly(ε‐caprolactone) and poly(vinyl alcohol)‐graft‐poly(lactide) in melt with magnesium hydride as catalyst

Grafting of poly(ε‐caprolactone) (PCL) and poly(lactide) (PLA) chains on poly(vinyl alcohol) backbone (PVA degree of hydrolysis 99%) was investigated using MgH₂ environmental catalyst and melt‐grown ring‐opening polymerization (ROP) of ε‐caprolactone (CL) and L ‐lactide (LA), that avoiding undesirable toxic catalyst and solvent. The ability of MgH₂ as catalyst as well as yield of reaction were discussed according to various PVA/CL/MgH₂ and PVA/LA/MgH₂ ratio. PVA‐g‐PCL and PVA‐g‐PLA were characterized by ¹H‐ and ¹³C‐NMR, DSC, SEC, IR. For graft copolymers easily soluble in tetrahydrofuran (THF) or chloroform, wettability and surface energy of cast film varied in relation with the length and number of hydrophobic chains. Aqueous solution of micelle‐like particles was realized by dissolution in THF then addition of water. Critical micelle concentration (CMC) decreased with hydrophobic chains. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and thermal properties of poly(methyl methacrylate)‐poly(L‐lactic acid)‐poly(methyl methacrylate) tri‐block copolymer

Poly(methyl methacrylate)‐poly(L ‐lactic acid)‐poly(methyl methacrylate) tri‐block copolymer was prepared using atom transfer radical polymerization (ATRP). The structure and properties of the copolymer were analyzed using infrared spectroscopy, gel permeation chromatography, nuclear magnetic resonance (¹H‐NMR, ¹³C‐NMR), thermogravimetry, and differential scanning calorimetry. The kinetic plot for the ATRP of methyl methacrylate using poly(L ‐lactic acid) (PLLA) as the initiator shows that the reaction time increases linearly with ln[M]₀/[M]. The results indicate that it is possible to achieve grafted chains with well‐defined molecular weights, and block copolymers with narrowed molecular weight distributions. The thermal stability of PLLA is improved by copolymerization. A new wash‐extraction method for removing copper from the ATRP has also exhibits satisfactory results. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and characterization of biodegradable poly(ester‐urethanes) based on bacterial poly(R‐3‐hydroxybutyrate)

A series of poly(R‐3‐hydroxybutyrate)/poly(ε‐caprolactone)/1,6‐hexamethylene diisocyanate‐segmented poly(ester‐urethanes), having different compositions and different block lengths, were synthesized by one‐step solution polymerization. The molecular weight of poly(R‐3‐hydroxybutyrate)‐diol, PHB‐diol, hard segments was in the range of 2100–4400 and poly(ε‐caprolactone)‐diol, PCL‐diol, soft segments in the range of 1080–5800. The materials obtained were investigated by using differential scanning calorimetry, wide angle X‐ray diffraction and mechanical measurements. All poly(ester‐urethanes) investigated were semicrystalline with T_m varying within 126–148°C. DSC results showed that T_g are shifted to higher temperature with increasing content of PHB hard segments and decreasing molecular weight of PCL soft segments. This indicates partial compatibility of the two phases. In poly(ester‐urethanes) made from PCL soft segments of molecular weight (M_n ≥ 2200), a PCL crystalline phase, in addition to the PHB crystalline phase, was observed. As for the mechanical tensile properties of poly(ester‐urethane) cast films, it was found that the ultimate strength and the elongation at the breakpoint decrease with increasing PHB hard segment content. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 703–718, 2002     

Porous biodegradable polyesters. I. Preparation of porous poly(L‐lactide) films by extraction of poly(ethylene oxide) from their blends

Porous poly(L ‐lactide) (PLLA) films were prepared by water extraction of poly(ethylene oxide) (PEO) from solution‐cast PLLA and PEO blend films. The dependence of blend ratio and molecular weight of PEO on the porosity and pore size of films was investigated by gravimetry and scanning electron microscopy. The film porosity and extracted weight ratio were in good agreement with the expected for porous films prepared using PEO of low molecular weight (M_w = 1 × 10³), but shifted to lower values than expected when high molecular weight PEO (M_w = 1 × 10⁵) was utilized. The maximum pore size was larger for porous films prepared from PEO having higher molecular weight, when compared at the same blending ratio of PLLA and PEO before water extraction. Differential scanning calorimetry of as‐cast PLLA and PEO blend films revealed that PLLA and PEO were phase‐separated at least after solvent evaporation. On the other hand, comparison of blend films before and after extraction suggested that a small amount of PEO was trapped in the amorphous region between PLLA crystallites even after water extraction and hindered PLLA crystallization during solvent evaporation. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 629–637, 2000     

Synthesis of poly(1‐hexene)s end‐functionalized with phenols

Electrophilic alkylations of phenol/2,6‐dimethylphenol were performed with vinylidene‐terminated poly(1‐hexene)s using BF₃·OEt₂ catalyst. Vinylidene‐terminated poly(1‐hexene)s with M_n varying from 400 to 10000 were prepared by bulk polymerization of 1‐hexene at 50 to ?20 °C using Cp₂ZrCl₂/MAO catalysts. The phenol/2,6‐dimethylphenol‐terminated poly(1‐hexene)s was characterized by NMR (¹H, ¹³C), UV, IR and vapor phase osmometer (VPO). The isomer distribution (ortho, para and ortho/para) was determined by ¹³P NMR using a phosphitylating reagent, namely 2‐chloro‐1,3,2‐dioxaphospholane. The number‐average degree of functionality (F_n) >0.9 with >95% para selectivity could be achieved using low‐molecular‐weight oligomers of poly(1‐hexene)s. Copyright © 2005 Society of Chemical Industry     

New poly(1,3,4‐oxadiazole)s bearing pentadecyl side chains: Synthesis and characterization

The 4‐[4′‐(Hydrazinocarbonyl)phenoxy]‐2‐pentadecylbenzohydrazide was polycondensed with aromatic diacid chlorides viz., terephthalic acid chloride (TPC), isophthalic acid chloride (IPC), and a mixture of TPC : IPC (50 : 50 mol %) to obtain polyhydrazides which on subsequent cyclodehydration reaction in the presence of phosphoryl chloride yielded new poly(1,3,4‐oxadiazole)s bearing flexibilizing ether linkages and pentadecyl side chains. Inherent viscosities of polyhydrazides and poly(1,3,4‐oxadiazole)s were in the range 0.53–0.66 dL g^?1 and 0.49–0.53 dL g^?1, respectively, indicating formation of medium to reasonably high molecular weight polymers. The number average molecular weights (M_n) and polydispersities (M_w/M_n) of poly(1,3,4‐oxadiazole)s were in the range 14,660–21,370 and 2.2–2.5, respectively. Polyhydrazides and poly(1,3,4‐oxadiazole)s were soluble in polar aprotic solvents such as N,N‐dimethylacetamide, 1‐methyl‐2‐pyrrolidinone, and N,N‐dimethylformamide. Furthermore, poly(1,3,4‐oxadiazole)s were also found to be soluble in solvents such as chloroform, dichloromethane, tetrahydrofuran, pyridine, and m‐cresol. Transparent, flexible, and tough films of polyhydrazides and poly(1,3,4‐oxadiazole)s could be cast from N,N‐dimethylacetamide and chloroform solutions, respectively. Both polyhydrazides and poly(1,3,4‐oxadiazole)s were amorphous in nature and formation of layered structure was observed due to packing of pentadecyl chains. A decrease in glass transition temperature was observed both in polyhydrazides (143–166°C) and poly(1,3,4‐oxadiazole)s (90–102°C) which could be ascribed to “internal plasticization” effect of pentadecyl chains. The T₁₀ values, obtained from TG curves, for poly(1,3,4‐oxadiazole)s were in the range of 433–449°C indicating their good thermal stability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci 124:1281–1289, 2012     

Synthesis and characterization of poly(p‐phenylene)‐graft‐poly(ε‐caprolactone) copolymers by combined ring‐opening polymerization and cross‐coupling processes

2,5‐Dibromo‐1,4‐(dihydroxymethyl)benzene was used as initiator in ring‐opening polymerization of ε‐caprolactone in the presence of stannous octoate (Sn(Oct)₂) catalyst. The resulting poly(ε‐caprolactone) (PCL) macromonomer, with a central 2,5‐dibromo‐1,4‐diphenylene group, was used in combination with 1,4‐dibromo‐2,5‐dimethylbenzene for a Suzuki coupling in the presence of Pd(PPh₃)₄ as catalyst or using the system NiCl₂/bpy/PPh₃/Zn for a Yamamoto‐type polymerization. The poly(p‐phenylenes) (PPP) obtained, with PCL side chains, have solubility properties similar to those of the starting macromonomer, ie soluble in common organic solvents at room temperature. The new polymers were characterized by ¹H and ¹³C NMR and UV spectroscopy and also by GPC measurements. The thermal behaviour of the precursor PCL macromonomer and the final poly(p‐phenylene)‐graft‐poly(ε‐caprolactone) copolymers were investigated by thermogravimetric analysis and differential scanning calorimetry analyses and compared. Copyright © 2004 Society of Chemical Industry     

Highly enhanced accelerating effect of melt‐recrystallized stereocomplex crystallites on poly(L‐lactic acid) crystallization: effects of molecular weight of poly(D‐lactic acid)

The effects of the molecular weight of poly(D ‐lactic acid) (PDLA), which forms stereocomplex (SC) crystallites with poly(L ‐lactic acid) (PLLA), and those of processing temperature T_p on the acceleration (or nucleation) of PLLA homocrystallization were investigated using PLLA films containing 10 wt% PDLA with number‐average molecular weight (M_n) values of 5.47 × 10⁵, 9.67 × 10⁴ and 3.67 × 10⁴ g mol^–1 (PDLA‐H, PDLA‐M and PDLA‐L, respectively). For the PLLA/PDLA‐H and PLLA/PDLA‐M films, the SC crystallites that were ‘non’‐melted and those that were ‘completely’ melted at T_p values just above their endset melting temperature and recrystallized during cooling were found to act as effective accelerating (or nucleation) agents for PLLA homocrystallization. In contrast, SC crystallites formed from PDLA‐L, having the lowest M_n, were effective accelerating agents without any restrictions on T_p. In this case, the accelerating effects can be attributed to the plasticizer effect of PDLA‐L with the lowest M_n. The accelerating effects of SC crystallites in the PLLA/PDLA‐H and PLLA/PDLA‐M films was dependent on crystalline thickness for T_p values below the melting peak temperature of SC crystallites, whereas for T_p values above the melting peak temperature the accelerating effects are suggested to be affected by the interaction between the SC crystalline regions and PLLA amorphous regions.     

Relationship between the crystallization behavior of poly(ethylene glycol) and stereocomplex crystallization of poly(L‐lactic acid)/poly(D‐lactic acid)

Poly(l ‐lactic acid) (PLLA) is a good biomedical polymer material with wide applications. The addition of poly(ethylene glycol) (PEG) as a plasticizer and the formation of stereocomplex crystals (SCs) have been proved to be effective methods for improving the crystallization of PLLA, which will promote its heat resistance. In this work, the crystallization behavior of PEG and PLLA/poly(d ‐lactic acid) (PDLA) in PLLA/PDLA/PEG and PEG‐b‐PLLA/PEG‐b‐PDLA blends has been investigated using differential scanning calorimetry, polarized optical microscopy and X‐ray diffraction. Both SCs and homocrystals (HCs) were observed in blends with asymmetric mass ratio of PLLA/PDLA, while exclusively SCs were observed in blends with approximately equal mass ratio of PLLA/PDLA. The crystallization of PEG was only observed for the symmetric blends of PLLA_39k/PDLA_35k/PEG_2k, PLLA_39k/PDLA_35k/PEG_5k, PLLA_69k/PDLA_96k/PEG_5k and PEG‐b‐PLLA_31k/PEG‐b‐PDLA_27k, where the mass ratio of PLLA/PDLA was approximately 1/1. The results demonstrated that the formation of exclusively SCs would facilitate the crystallization of PEG, while the existence of both HCs and SCs could restrict the crystallization of PEG. The crystallization of PEG is related to the crystallinity of PLLA and PDLA, which will be promoted by the formation of SCs. © 2017 Society of Chemical Industry     

Carbon dioxide sorption and diffusion in poly(3‐hydroxybutyrate) and poly(3‐hydroxybutyrate‐CO‐3‐hydroxyvalerate)

CO₂ sorption and diffusion in poly(3‐hydroxybutyrate) and three poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) copolymers were investigated gravimetrically at temperatures from 25° to 50°C and pressures up to 1 atm. The sorption behavior proved to be linear for all the copolymers studied. An additional set of measurements performed in a pressure decay apparatus at 35°C showed that the linearity could be extrapolated to pressures up to 25 atm. The sorption results obtained from both techniques were in good agreement. The poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) sorption kinetics were increasingly non‐Fickian at the higher temperatures, thus preventing the calculation of diffusion coefficients above 35°C. Interestingly, this was not the case for poly(3‐hydroxybutyrate), and diffusion coefficients and permeabilities could be calculated at all of the investigated temperatures. The 35°C permeabilities were fairly low, which is attributed to the high degree of crystallinity of this polyester family. Finally, the poly(3‐hydroxybutyrate) barrier properties against CO₂ are successfully compared with those of some selected common thermoplastics. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2391–2399, 1999     

The synthesis of poly(3‐hydroxybutyrate)‐g‐poly(methylmethacrylate) brush type graft copolymers by atom transfer radical polymerization method

Brush type of poly (3‐hydroxy butyrate), PHB, copolymer synthesis has been reported. Natural PHB was chlorinated by passing chlorine gas through PHB solution in CHCl₃/CCl₄ mixture (75/25 v/v) to prepare chlorinated PHB, PHB‐Cl, with the chlorine contents varying between 2.18 and 39.8 wt %. Toluene solution of PHB‐Cl was used in the atom transfer radical polymerization (ATRP) of methyl methacrylate, MMA, in the presence of cuprous bromide (CuBr)/2,2′‐bipyridine complex as catalyst, at 90°C. This “grafting from” technique led to obtain poly (3‐hydroxybutyrate)‐g‐poly(methylmethacrylate) (PHB‐g‐PMMA) brush type graft copolymers (cylindrical brush). The polymer brushes were fractionated by fractional precipitation methods and the γ values calculated from the ratio of the volume of nonsolvent to volume of solvent of brushes were ranged between 2.8 and 9.5 depending on the molecular weight, grafting density, and side chain length of the brushes, while the γ values of PHB, PHB‐Cl, and homo‐PMMA were 2.7–3.8, 0.3–2.4, and 3.0–3.9, respectively. The fractionated brushes were characterized by gel permeation chromatography, ¹H‐NMR spectrometry, thermogravimetric analysis (TGA), and differential scanning calorimetry techniques. PHB‐g‐PMMA brush type graft copolymers showed narrower molecular weight distribution (mostly in range between 1.3 and 2.2) than the PHB‐Cl macroinitiator (1.6–3.5). PHB contents in the brushes were calculated from their TGA thermograms and found to be in range between 22 and 42 mol %. The morphologies of PHB‐g‐PMMA brushes were also studied by scanning electron microscopy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis of amphiphilic temperature‐sensitive poly(N‐isopropylacrylamide)‐block‐poly(tetramethylene carbonate) block copolymers and micellar characterization

Amphiphilic thermally sensitive poly(N‐isopropylacrylamide)‐block‐poly(tetramethylene carbonate) block copolymers were synthesized by ring‐opening polymerization of tetramethylene carbonate with hydroxyl‐terminated poly(N‐isopropylacrylamide) (PNiPAAm) as macro‐initiator in the presence of stannous octoate as catalyst. The synthesis involved PNiPAAm bearing a single terminal hydroxyl group prepared by telomerization using 2‐hydroxyethanethiol as a chain‐transfer agent. The copolymers were characterized using ¹H NMR and Fourier transform infrared spectroscopy and gel permeation chromatography. Their solutions show reversible changes in optical properties: transparent below the lower critical solution temperature (LCST) and opaque above the LCST. The LCST depends on the polymer composition and the media. Owing to their amphiphilic characteristics, the block copolymers form micelles in the aqueous phase with critical micelle concentrations (CMCs) in the range 1.11–22.9 mg L^?1. Increasing the hydrophobic segment length or decreasing the hydrophilic segment length in the amphiphilic diblock copolymers produces lower CMCs. A core‐shell structure of the micelles is evident from ¹H NMR analyses of the micelles in D₂O. Transmission electron microscopic analyses of micelle morphology show a spherical structure of both blank and drug‐loaded micelles. The blank and drug‐loaded micelles have an average size of less than 130 nm. Observations show high drug‐entrapment efficiency and drug‐loading content for the drug‐loaded micelles. Copyright © 2010 Society of Chemical Industry     

Preparation and characterization of castor oil‐based polyurethane/poly(o‐methoxyaniline) blend film

Blends made up of castor oil‐based polyurethane (PU) and poly(o‐methoxyaniline) (POMA) were obtained in the form of films by casting and characterized by FTIR, UV‐Vis‐NIR spectroscopy, and electrical conductivity measurements. Doping was carried out by immersing the films in 1.0M HCl aqueous solution. Chemical bonds between NCO group of PU and NH group of POMA were observed by means of FTIR spectra. The UV‐Vis‐NIR spectra indicated that the presence of the PU in the blend does not affect doping and formation of the POMA phase. The electrical conductivity research was in the range of 10^?3 S/cm. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Miscibility and phase structure of binary blends of poly(L‐lactide) and poly(vinyl alcohol)

Blend films of poly(L ‐lactide) (PLLA) and poly(vinyl alcohol) (PVA) were obtained by evaporation of hexafluoroisopropanol solutions of both components. The component interaction, crystallization behavior, and miscibility of these blends were studied by solid‐state NMR and other conventional methods, such as Fourier transform infrared (FTIR) spectra, differential scanning calorimetry (DSC), and wide‐angle X‐ray diffraction (WAXD). The existence of two series of isolated and constant glass‐transition temperatures (T_g's) independent of the blend composition indicates that PLLA and PVA are immiscible in the amorphous region. However, the DSC data still demonstrates that some degree of compatibility related to blend composition exists in both PLLA/atactic‐PVA (a‐PVA) and PLLA/syndiotactic‐PVA (s‐PVA) blend systems. Furthermore, the formation of interpolymer hydrogen bonding in the amorphous region, which is regarded as the driving force leading to some degree of component compatibility in these immiscible systems, is confirmed by FTIR and further analyzed by ¹³C solid‐state NMR analyses, especially for the blends with low PLLA contents. Although the crystallization kinetics of one component (especially PVA) were affected by another component, WAXD measurement shows that these blends still possess two isolated crystalline PLLA and PVA phases other than the so‐called cocrystalline phase. ¹³C solid‐state NMR analysis excludes the interpolymer hydrogen bonding in the crystalline region. The mechanical properties (tensile strength and elongation at break) of blend films are consistent with the immiscible but somewhat compatible nature of these blends. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 762–772, 2001