Miscible blends containing bacterial poly(3‐hydroxyvalerate) and poly(p‐vinyl phenol)

The miscibility of poly(3‐hydroxyvalerate) (PHV)/poly(p‐vinyl phenol) (PVPh) blends has been studied by differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy. The blends are miscible as shown by the existence of a single glass transition temperature (T_g) and a depression of the equilibrium melting temperature of PHV in each blend. The interaction parameter was found to be −1.2 based on the analysis of melting point depression data using the Nishi–Wang equation. Hydrogen‐bonding interactions exist between the carbonyl groups of PHV and the hydroxyl groups of PVPh as evidenced by FTIR spectra. The crystallization of PHV is significantly hindered by the addition of PVPh. The addition of 50 wt % PVPh can totally prevent PHV from cold crystallization. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 383–388, 1999     

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     

Miscibility study of poly(vinyl chloride)/poly(methyl methacrylate‐co‐4‐vinylpyridine) by viscosimetry,DSC, and FTIR

The miscibility of the poly(vinyl chloride)/poly(methylmethacrylate) system were improved by introducing pyridine units into poly(methylmethacrylate) main. For this purpose, we have synthesized through a radical polymerization a series of methylmethacrylate‐co‐vinyl‐4‐pyridine copolymers of different compositions and carried out a comparative study by viscosimetry, differential scanning calorimetry, and Fourier transform infrared spectroscopic (FTIR) methods. The viscosimetric analysis using the Krigbaum‐Wall, K. K. Chee, and Compos approaches revealed that, the Poly(vinyl chloride)/poly(methylmethactylate‐co‐4‐vinylpyridine)(PVC/MMA4VP‐15) at 15 wt % of 4‐vinylpyridine systems in tetrahydrofuran are completely miscible in all proportions. The differential scanning calorimetry analysis confirmed the miscibility of these systems in all proportions by the appearance of only one glass transition temperature between those of the two pure constituents. The Kwei and Schneider approaches showed also the miscibility of this system, which is due to the specific interactions between the acidic hydrogen atom of PVC and the nitrogen of MMA4VP‐15. The use of FTIR method has confirmed the occurrence of this kind of interactions by broadening and shifting of the involved functional groups vibration bands. In this work, we have also carried out a preliminary test of sorption of THF aqueous solution by PVC and PVC/MMA4VP‐15 blend membranes. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Miscibility enhancement through hydrogen bonding interaction of biodegradable poly(3‐hydroxybutyrate) blending with poly(styrene‐co‐vinyl phenol) copolymer

Differential scanning calorimetry, one‐ and two‐dimensional Fourier transform infrared (FTIR), and solid state nuclear magnetic resonance (NMR) spectroscopy have been used to investigate the miscibility of and specific interactions between poly(styrene‐co‐vinyl phenol) (PSOH) and poly(3‐hydroxybutyrate) (PHB) upon varying the vinyl phenol content of the PSOH copolymer. The FTIR and solid state NMR spectra revealed that the phenol units of PVPh interact with the carbonyl groups of PHB through intermolecular hydrogen bonding. A miscibility window exists when the vinyl phenol fraction in the copolymer is greater than 22 mol % in the PSOH/PHB blend system, as predicted using the Painter–Coleman association model. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Miscibility of polymer blends of poly(styrene‐co‐4‐hydroxystyrene) with bisphenol‐A polycarbonate

The miscibility of blends of bisphenol‐A polycarbonate (BAPC) and tetramethyl bisphenol‐A polycarbonate (TMPC) with copolymers of poly(styrene‐co‐4‐hydroxystyrene) (PSHS) was studied in this work. It has been demonstrated that BAPC is miscible with PSHS over a region of approximately 45–75 mol % hydroxyl groups in the copolymer. TMPC has a wider miscible window than BAPC when blended with PSHS. The blend miscibility was considered to be driven by the intermolecular attractive interactions between the hydroxyl groups of the PSHS and the π electrons of the aromatic rings of both polycarbonates (PCs). As the FTIR measurements showed, after blending of BAPC with PSHS, there is no visible shift of the carbonyl band of BAPC at 1774 cm⁻¹, whereas the stretching frequency of the free hydroxyl groups of the copoly‐ mers at 3523 cm⁻¹ disappeared. The large positive values of the segment interaction energy density parameter B_st‐HS calculated from the group contribution approach indicated that the intramolecular repulsive interaction may also have played a role in the promotion of the blend miscibility. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 639–646, 1999     

Synthesis and properties of hydrophilic segmented block copolymers based on poly(ethylene oxide)‐ran‐poly(propylene oxide)

The present article discusses the synthesis and various properties of segmented block copolymers with random copolymer segments of poly(ethylene oxide) and poly(propylene oxide) (PEO‐r‐PPO) together with monodisperse amide segments. The PEO‐r‐PPO contained 25 wt % PPO units and the segment presented a molecular weight of 2500 g/mol. The synthesized copolymers were analyzed by differential scanning calorimetry, Fourier transform infra‐red spectroscopy, atomic force microscopy and dynamic mechanical thermal analysis. In addition, the hydrophilicity and the contact angles (CAs) were studied. The PEO‐r‐PPO segments displayed a single low glass transition temperature, as well as a low PEO crystallinity and melting temperature, which gave enhanced low‐temperature properties of the copolymer. The water absorption values remained high. In comparison to mixtures of PEO/PPO segments, the random dispersion of PPO units in the PEO segments was more effective in reducing the PEO crystallinity and melting temperature, without affecting the hydrophilicity. Increasing the polyether segment length with terephthalic groups from 2500 to 10,000 g/mol increased the hydrophilicity and the room temperature elasticity. Furthermore, the CAs were found to be low 22–39° and changed with the crosslink density. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117:1394–1404, 2010     

Miscibility and intermolecular hydrogen‐bonding interactions in poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate)/poly(4‐vinyl phenol) binary blends

The miscibility and hydrogen bonding interaction in the poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate)/poly(4‐vinyl phenol) [P(3HB‐co‐3HH)/PVPh] binary blends were investigated by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The DSC results indicate that P(3HB‐co‐3HH) with 20 mol % 3HH unit content is fully miscible with PVPh, and FTIR studies reveal the existence of hydrogen bonding interaction between the carbonyl groups of P(3HB‐co‐3HH) and the hydroxyl groups of PVPh. The effect of blending of PVPh on the mechanical properties of P(3HB‐co‐3HH) were studied by tensile testing. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Miscibility of C60‐containing poly(methyl methacrylate)/poly(vinylidene fluoride) blends

The miscibility of C₆₀‐containing poly(methyl methacrylate) (PMMA‐C₆₀) with poly(vinylidene fluoride) (PVDF) was studied. Two PMMA‐C₆₀ samples containing 2.6 and 7.4 wt % C₆₀ were found to be miscible with PVDF based on single glass transition temperature criterion and melting point depression of PVDF. However, the interaction parameters of the two blend systems are less negative than that of the PMMA/PVDF blend system, showing that the incorporation of C₆₀ reduces the ability of carbonyl groups of PMMA to interact with PVDF. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1393–1396, 2000     

Synthesis and characterization of poly(L‐lactide)‐poly(ethylene glycol) multiblock copolymers

Poly(L‐lactide)‐poly(ethylene glycol) multiblock copolymers with predetermined block lengths were synthesized by polycondensation of PLA diols and PEG diacids. The reaction was carried out under mild conditions, using dicyclohexylcarbodiimide as the coupling agent and dimethylaminopyridine as the catalyst. The resulting copolymers were characterized by various analytical techniques, such as GPC, viscometry, ¹H‐NMR, FTIR, DSC, X‐ray diffractometry, and contact angle measurement. The results indicated that these copolymers presented outstanding properties pertinent to biomedical use, including better miscibility between the two components, low crystallinity, and hydrophilicity. Moreover, the properties of the copolymers can be modulated by adjusting the block length of the two components or the reaction conditions. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1729–1736, 2002; DOI 10.1002/app.10580     

Biodegradable blends of high molecular weight poly(ethylene oxide) with poly(3‐hydroxypropionic acid) and poly(3‐hydroxybutyric acid): a miscibility study by DSC,DMTA and NMR spectroscopy

The miscibility of high molecular weight poly(ethylene oxide) blends with poly(3‐hydroxypropionic acid) and poly(3‐hydroxybutyric acid) (P(3HB)) has been investigated by differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA) and high‐resolution solid state ¹³C nuclear magnetic resonance (NMR). The DSC thermal behaviour of the blends revealed that the binary blends of poly(ethylene oxide)/poly(3‐hydroxypropionic acid) (OP blends) were miscible over the whole composition range while the miscibility of poly(ethylene oxide)/poly(3‐hydroxybutyric acid) blends (OB blends) was dependent on the blend composition. OB blends were found to be partly miscible at the middle P(3HB) contents (25 %, 50 %) and miscible at other P(3HB) contents (10 %, 75 % and 90 %). Single‐phase behaviour for OP blends and phase separation behaviour for OB blends were observed from DMTA. The results from NMR spectroscopy revealed that the two components in the OP50 blend were intimately mixed on a scale of about 35 nm, while the domain sizes in the OB blend with a P(3HB) content of 50 % were larger than about 32 nm. © 2000 Society of Chemical Industry     

Grafting of poly(3‐hydroxyalkanoate) and linoleic acid onto chitosan

Poly(3‐hydroxy octanoate) (PHO), poly(3‐hydroxy butyrate‐co‐3‐hydroxyvalerate) (PHBV), and linoleic acid were grafted onto chitosan via condensation reactions between carboxylic acids and amine groups. Unreacted PHAs and linoleic acid were eliminated via chloroform extraction and for elimination of unreacted chitosan were used 2 wt % of HOAc solution. The pure chitosan graft copolymers were isolated and then characterized by FTIR, ¹³C‐NMR (in solid state), DSC, and TGA. Microbial polyester percentage grafted onto chitosan backbone was varying from 7 to 52 wt % as a function of molecular weight of PHAs, namely as a function of steric effect. Solubility tests were also performed. Graft copolymers were soluble, partially soluble or insoluble in 2 wt % of HOAc depending on the amount of free primary amine groups on chitosan backbone or degree of grafting percent. Thermal analysis of PHO‐g‐Chitosan graft copolymers indicated that the plastizer effect of PHO by means that they showed melting transitions T_ms at 80, 100, and 113°C or a broad T_ms between 60.5–124.5°C and 75–125°C while pure chitosan showed a sharp T_m at 123°C. In comparison of the solubility and thermal properties of graft copolymers, linoleic acid derivatives of chitosan were used. Thus, the grafting of poly(3‐hydroxyalkanoate) and linoleic acid onto chitosan decrease the thermal stability of chitosan backbone. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103:81–89, 2007     

Interpolymer‐specific interactions and miscibility in poly(styrene‐co‐acrylic acid)/poly(styrene‐co‐N,N‐dimethylacrylamide) blends

The miscibility or complexation of poly(styrene‐co‐acrylic acid) containing 27 mol % of acrylic acid (SAA‐27) and poly(styrene‐co‐N,N‐dimethylacrylamide) containing 17 or 32 mol % of N,N‐dimethylacrylamide (SAD‐17, SAD‐32) or poly(N,N‐dimethylacrylamide) (PDMA) were investigated by different techniques. The differential scanning calorimetry (DSC) analysis showed that a single glass‐transition temperature was observed for all the mixtures prepared from tetrahydrofuran (THF) or butan‐2‐one. This is an evidence of their miscibility or complexation over the entire composition range. As the content of the basic constituent increases as within SAA‐27/SAD‐32 and SAA‐27/PDMA, higher number of specific interpolymer interactins occurred and led to the formation of interpolymer complexes in butan‐2‐one. The qualitative Fourier transform infrared (FTIR) spectroscopy study carried out for SAA‐27/SAD‐17 blends revealed that hydrogen bonding occurred between the hydroxyl groups of SAA‐27 and the carbonyl amide of SAD‐17. Quantitative analysis carried out in the 160–210°C temperature range for the SAA‐27 copolymer and its blends of different ratios using the Painter–Coleman association model led to the estimation of the equilibrium constants K₂, K_A and the enthalpies of hydrogen bond formation. These blends are miscible even at 180°C as confirmed from the negative values of the total free energy of mixing ΔG_M over the entire blend composition. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1011–1024, 2007     

Miscibility and crystallization behavior of the solution‐blended sulfonated poly(phenylene oxide)/ poly(styrene‐co‐4‐vinyl pyridine) blend

The miscibility and crystallization behavior of the solution‐blended lightly sulfonated poly(phenylene oxide) (SPPO)/poly(styrene‐co‐4‐vinylpyridine) (PSVP) blend were investigated by conventional and modulated differential scanning calorimetry (MDSC). It was found that the original blend film is actually composed of a crystalline SPPO phase and a noncrystalline compatible SPPO–PSVP phase. The original phase‐segregated structure will evolve to a noncrystalline homogenous structure by subsequent high temperature annealing. The resulting good miscibility was attributed to two aspects: one is that the SPPO crystalline structure could be destroyed as annealing temperature is high enough; the other is that the acid–base interaction between the sulfonic group of SPPO and the pyridine ring of PSVP could promote mixing of different components effectively. And such acid–base interaction was demonstrated by ¹C NMR spectra. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2843–2848, 2001     

Thermal,mechanical, and morphological characterization studies of poly(2,6‐dimethyl‐1,4‐phenylene oxide) blends with polystyrene and brominated polystyrene

The miscibility of the binary and ternary blends of poly(2,6‐dimethyl‐1,4‐phenylene oxide), brominated polystyrene, and polystyrene was investigated using a differential scanning calorimeter. The morphology of these blends was characterized by scanning electron microscopy. These studies revealed a close relation between the blend structure and its mechanical properties. The compatibilizing effect of poly(2,6‐dimethyl‐1,4‐phenylene oxide) on the miscibility of the polystyrene/brominated polystyrene blends was examined. It was found that poly(2,6‐dimethyl‐1,4‐phenylene oxide), which was miscible with polystyrene and partially miscible with brominated polystyrene, compatibilizes these two immiscible polymers if its contention exceeds 33 wt %. Upon the addition of poly(2,6‐dimethyl‐1,4‐phenylene oxide) to the immiscible blends of polystyrene/brominated polystyrene, we observed a change in the morphology of the mixtures. An improvement in the mechanical properties was noticed. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 225–231, 2000     

Molecular interactions in poly(methacrylic acid)/poly(N‐isopropyl acrylamide) interpenetrating polymer networks

The molecular interactions between the component networks in poly(methacrylic acid)/poly(N‐isopropyl acrylamide) (PMAA/PNIPAAm) interpenetrating polymer networks (IPNs) were investigated using attenuated total reflectance (ATR)‐Fourier transform IR (FTIR) spectroscopy. Hydrogen‐bond formation was noted between the carboxyl groups of PMAA and the amide groups of PNIPAAm. The ATR‐FTIR results showed shifts in the carboxylic and amide groups, indicating the existence of hydrogen bonding between these two individual networks within the IPNs. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1077–1082, 2001     

Effect of tacticity of poly(methyl methacrylate) on the miscibility with poly(styrene‐co‐acrylonitrile)

Isotactic, atactic, and syndiotactic poly(methyl methacrylates) (PMMAs) (designated as iPMMA, aPMMA, and sPMMA) with approximately the same molecular weight were mixed separately with poly(styrene‐co‐acrylonitrile) (abbreviated as PSAN) containing 25 wt % of acrylonitrile in tetrahydrofuran to make three polymer blend systems. Differential scanning calorimetry (DSC) was used to study the miscibility of these blends. The results showed that the tacticity of PMMA has a definite impact on its miscibility with PSAN. The aPMMA/PSAN and sPMMA/PSAN blends were found to be miscible because all the prepared films were transparent and showed composition dependent glass transition temperatures (T_gs). The glass transition temperatures of the two miscible blends were fitted well by the Fox equation, and no broadening of the glass transition regions was observed. The iPMMA/PSAN blends were found to be immiscible, because most of the cast films were translucent and had two glass transition temperatures. Through the use of a simple binary interaction model, the following comments can be drawn. The isotactic MMA segments seemed to interact differently with styrene and with acrylonitrile segments from atactic or syndiotactic MMA segments. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2894–2899, 1999     

Miscibility of block copolymers of poly(ε‐caprolactone) and poly(ethylene glycol) with poly(3‐hydroxybutyrate) as well as the compatibilizing effect of these copolymers in blends of poly(ε‐caprolactone) and poly(3‐hydroxybutyrate)

Atactic poly(3‐hydroxybutyrate) (a‐PHB) and block copolymers of poly(ethylene glycol) (PEG) with poly(ε‐caprolactone) (PCL‐b‐PEG) were synthesized through anionic polymerization and coordination polymerization, respectively. As demonstrated by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) measurements, both chemosynthesized a‐PHB and biosynthesized isotactic PHB (i‐PHB) are miscible with the PEG segment phase of PCL‐b‐PEGs. However, there is no evidence showing miscibility between both PHBs and the PCL segment phase of the copolymer even though PCL has been block‐copolymerized with PEG. Based on these results, PCL‐b‐PEG was added, as a compatibilizer, to both the PCL/a‐PHB blends and the PCL i‐PHB blends. The blend films were obtained through the evaporation of chloroform solutions of mixed components. Excitingly, the improvement in mechanical properties of PCL/PHB blends was achieved as anticipated initially upon the addition of PCL‐b‐PEG. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2600–2608, 2001     

Miscibility,crystallization, and mechanical properties of poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate)/ poly(butylene succinate) blends

Naturally amorphous biopolyester poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) (P3/4HB) containing 21 mol % of 4HB was blended with semi‐crystal poly(butylene succinate) (PBS) with an aim to improve the properties of aliphatic polyesters. The effect of PBS contents on miscibility, thermal properties, crystallization kinetics, and mechanical property of the blends was evaluated by DSC, TGA, FTIR, wide‐angle X‐ray diffractometer (WAXD), Scanning Electron Microscope (SEM), and universal material testing machine. The thermal stability of P3/4HB was enhanced by blending with PBS. When PBS content is less than 30 wt %, the two polymers show better miscibility and their crystallization trend was enhanced by each other. The optimum mechanical properties were observed at the 5–10 wt % PBS blends. However, when the PBS content is more than 30 wt %, phase inversion happened. And the two polymers give lower miscibility and poor mechanical properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Novel biodegradable amphiphilic poly(ε‐caprolactone)/poly(N‐vinylpyrrolidone) blends via successive in situ polymerizations

In this study, biodegradable blends of poly(ε‐caprolactone) (PCL) and poly(N‐vinylpyrrolidone) (PVP) were prepared by a new strategy in the following steps: (1) free radical polymerization of N‐vinyl‐2‐pyrrolidone (NVP) in ε‐caprolactone (CL); (2) ring‐opening polymerization of ε‐caprolactone in the presence of PVP to obtain the target blends. The structure of the blends was confirmed by FTIR and ¹H NMR, and the molecular weight of PCL and PVP were determined by GPC. SEM study revealed that this polymerization method could decrease the disperse phase size and improve the interphase when compared with solution‐blending method. The phase inversion occurred when PVP content was 15–20 wt %. Subsequently, the PCL sphere dispersed in PVP matrix and its size decreased with the increase of PVP content. The contact angle results showed that PVP has a profound effect on hydrophilic properties of PCL/PVP blends. PCL/PVP blends are believed to be promising for drug delivery, cell therapy, and other biomedical applications. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Novel FTIR method for determining the crystallinity of poly(ε‐caprolactone)

By employing Fourier transform infrared spectroscopy (FTIR) and curve–fitting techniques, the degree of crystallinity of poly(ε‐caprolactone) (PCL) aged at room temperature for 1 month was estimated to be 49 ± 2 %. The degree of crystallinity determined by FTIR in this work is comparable with those found by other conventional techniques. It is suggested that the FTIR procedure established here for the crystallinity determination of PCL should also be suitable for the quantitative analysis of solid‐state morphology of polymers containing carbonyl or other functional groups. © 2000 Society of Chemical Industry