Reactive compatibilization of nylon copolymer/EPDM blends: experimental aspects and their comparison with theory

In situ reactive compatibilization was first time applied to a low melting nylon (nylon 6 and 66 copolymer) and EPDM blend system. The effects of in situ compatibilization and concentration of compatibilizer on the morphology and mechanical properties of nylon/EPDM blends have been investigated. The influence of EPM‐g‐MA on the phase morphology was examined by the scanning electron microscopy (SEM) after preferential extraction of the minor phase. The SEM micrographs were quantitatively analyzed for domain size measurements. The compatibilizer concentrations used were 0, 1, 2.5, 5, and 10 wt%. The graft copolymer (nylon‐g‐EPM) formed at the interface showed relatively high emulsifying activity. A maximum phase size reduction was observed when 2.5 wt% of compatibilizer was added to the blend system. This was followed by a leveling‐off at higher loadings indicating interfacial saturation. The conformation of the compatibilizer at the interface was deduced based on the area occupied by the compatibilizer at the blend interface. The experimental compatibilization results were compared with theoretical predictions of Noolandi and Hong. It was concluded that the molecular state of compatibilizer at interface changes with concentration. The in situ compatibilized blends showed considerable improvement in mechanical properties. Measurement of tensile properties shows increased elongation as well as enhanced modulus and strength up on compatibilization. At higher concentrations of compatibilizer, a leveling‐off of the tensile properties was observed. A good correlation has been observed between the mechanical properties and morphological parameters. Copyright © 2007 John Wiley & Sons, Ltd.     

Reactive compatibilization of blends of PET and PP modified by GMA grafting

The melt radical grafting of glycidyl methacrylate (GMA) onto isotactic polypropylene (PP) was carried out in Brabender internal mixer and the influence of reaction procedure, radical initiator concentration and addition of co-monomer (styrene) on the grafting efficiency was examined. The viscosity, the thermal behaviour and melt rheology of PP-g-GMA samples was then analysed as a function of grafted GMA content. Blends of poly(ethylene terephthalate) (PET) with PP and PP-g-GMA (5.2 wt% GMA), prepared in internal mixer, were characterised by SEM, DSC and melt viscosimetry. The morphological analysis of PET/PP-g-GMA blends (80/20, 50/50 w/w) pointed out a marked improvement of phase dispersion (with particle size of about 0.6 μm for 80/20 blend) and interfacial adhesion, as compared to non-compatibilized PET/PP blend. The results of mixing torque and thermal analysis supported the occurrence of in-situ compatibilization reaction between epoxy groups of GMA modified PP and carboxyl end-groups of PET in the melt.     

Design,polymerization, and properties of polyurethane elastomers from miscible,immiscible, and hybridized seed‐oil derived soft segment blends

Polyester seed‐oil derived polyols have been prepared and blended with conventional polyols for making polyurethane elastomers. Miscibility was complete for polypropylene oxide/polyethylene oxide and polytetramethylene oxide (PTMEG). Blends of polyester seed‐oil derived polyols with conventional polyester polyols (polybutylene adipate and ?‐polycaprolactone) were immiscible or nearly so. Furthermore, the phase behavior (miscible vs. immiscible) did not change appreciably for each blend composition explored as a function of temperature at relevant ranges (up to the polyether ceiling temperature). This counter‐intuitive result is found to be actually consistent with calculated solubility parameters for each polyol type and the phase diagrams computed on their basis. The phase behavior of the polyols is shown to have significant effects on the properties of polyurethane elastomers where immiscible polyols cause broadening of the glass transition distribution and significant reduction of ultimate tensile properties. However, here it is shown that immiscible systems containing polyester seed‐oil derived polyols can be transesterified with the appropriate polyol partner of interest to create a new single phase polyol or that the polyester polyol monomers can also be copolymerized to make new single phase polyols, both of which result in improved polyurethane elastomer properties. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 93–102     

Reactive processing with difunctional oligomers to compatibilize polymer blends

The addition of telechelic reactive oligomers to a polymer blend as a compatibilization process is investigated. The results presented in this paper suggest that this process provides a mechanism by which blocky copolymeric compatibilizers can be formed during processing, as demonstrated by the changes in the mechanical and optical properties of the phase separated polymer blends. The results also show, however, that the presence of unreacted smaller oligomers can act as a plasticizer in the blend and can thus detrimentally affect the mechanical properties of the blend if any remains after processing. Careful control of the mixing conditions or post processing thermal annealing may be required to minimize this potentially deleterious effect. However, the data suggest that this optimization is possible.     

Preparation and characterization of polyurethane electrical insulating coatings derived from novel soybean oil‐based polyol

As a viable alternative to the petrochemical polyols in polyurethanes (PUs), a new soybean oil‐based polyol (PSBO) with high functionality of hydroxyl groups and built‐in (preformed) urethane bonds was introduced. At first, a facile and improved method was developed for the transformation of epoxidized soybean oil (ESBO) to carbonated soybean oil (CSBO). Then ring‐opening reaction of carbonated oil with ethanolamine (ETA) led to the polyol. After characterization by conventional spectroscopic and analytical methods, PSBO was used for the formulation of novel one‐pack PU electroinsulating wire enamels. Tunable mechanical, thermal, and electrical properties for the final PUs were achieved by replacing 10 wt% of PSBO with poly(propylene glycol) (PPG) at different number average molecular weights of 725, 1000, 2000, 4000. Investigation of the results showed that these soy‐based PUs offer excellent thermal and electrical insulating properties. Copyright © 2009 John Wiley & Sons, Ltd.     

Biodiesel from soybean oil,castor oil and their blends

Even not being described in the EN 14112 standard, PDSC has been used for the determination of the biodiesel oxidative stability, by OIT and OT measurements. In this study, biodiesel blends were obtained by mixing soybean (BES) and castor (BEM) ethyl esters and its induction periods were measured by Rancimat and PDSC. The blends (BSM _X ) showed intermediate values of OSI, OT, and OIT, compared with BES and BEM. Although, the molar fraction of the components varied linearly in BSM _X , OSI, OT, and OIT values increased exponentially in relation to the castor biodiesel amount in the blends. Introduction of castor oil biodiesel increased the blend stability, so the BSM₃₀ blend reached the OSI limit of 6 h. OSI, OIT, and OT showed a high-linear correlation, pointing out that PDSC can be used in the analysis of this kind of biodiesel, with a smaller sample and analysis time, as compared to Rancimat. The use of biodiesel blends was a good alternative in the correction of the oxidative stability of the final product without the need of antioxidant addition.     

Synthesis of novel silicone modified acrylic resins and their film properties

New silicone modified acrylic resins were synthesized and some of their film properties were investigated. At first, macromer (MC) was synthesized by the condensation reaction of the reactive polysiloxane intermediate (Z-6018) and 2-hydroxyethyl methacrylate (HEMA) in toluene as solvent at 110°C under nitrogen atmosphere. Then, MC was reacted with 2-dimethylaminoethyl methacrylate (DMAEMA) at different mole ratios (1:1, 1:3, 1:5) by using benzoyl peroxide as initiator in toluene to obtain novel silicone acrylic resins. These resins were characterized by Fourier Transform Infrared Spectrometry (FT-IR), and their thermal properties were investigated using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) techniques. The properties of the films prepared from these resins were determined. The results showed that these resins are thermally stable polymers and all films are flexible, semi-gloss and have excellent drying, adhesion properties. Copyright © 2007 John Wiley & Sons, Ltd.     

Reactive compatibilization of epoxy/polyorganosiloxane blends

A new thermoset material based on DGEBA with polyaminosiloxane curing agents is presented. The system shows reaction-induced compatibilization which prevents coalescence of polysiloxane and DGEBA rich domains, leading to gradient structured morphologies. The influence of curing temperature and/or chemical nature of the siloxane on the morphology and surface microhardness were examined. When siloxane is pre-reacted with epoxypropylphenylether (EPPE), a more homogeneous material is obtained. Microhardness profiles on the material are strongly influenced by the extension of the compositional gradients.     

Specific interactions and phase behavior of ternary poly(2‐vinylpyridine)/poly(N‐vinyl‐2‐pyrrolidone)/bisphenol A blends

Hydrogen‐bonding interactions between bisphenol A (BPA) and two proton‐accepting polymers, poly(2‐vinylpyridine) (P2VPy) and poly(N‐vinyl‐2‐pyrrolidone) (PVP), were examined by Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). The Flory–Huggins interaction‐energy densities of BPA/P2VPy and BPA/PVP blends were determined by the melting point depression method. The interaction parameters for both BPA/P2VPy and BPA/PVP blend systems were negative, demonstrating the miscibility of BPA with P2VPy as well as PVP. The miscibility of ternary BPA/P2VPy/PVP blends was examined by DSC, optical observation, and solid‐state nuclear magnetic resonance spectroscopy. The experimental phase behavior of the ternary blend system agreed with the spinodal phase‐separation boundary calculated using the determined interaction‐energy densities. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1125–1134, 2002     

Thermal studies on polypropylene/polyamide‐6 blends modified by succinic anhydride and succinyl fluorescein grafted polypropylenes

This study investigates the role played by two different interface agents on the basis of atactic polypropylene in the continuous/disperse phase polypropylene/polyamide‐6 (PP/PA6) system. The two agents used were obtained at the authors' laboratories from an atactic polypropylene byproduct derived from industrial polymerization reactors and consist of two grafted polymers containing either succinic anhydride (a‐PP‐SA) or both succinyl‐fluorescein and succinic anhydride grafted groups (a‐PP‐SF/SA). The role of these grafted polymers as compatibilizers in PP/PA6 polymer blends has been confirmed in previous investigations on the basis of their macroscopic behavior. This work investigates the thermal study of these blends where polypropylene acts as the polymer matrix and polyamide as the dispersed phase. Under isothermal conditions, thermal analysis agrees with the changes in the overall system behavior caused by the presence of the interface agents. These aspects were confirmed by polarized light microscopy that showed the morphology of the blends before and after modification with a‐PP‐SA or a‐PP‐SF/SA. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1307–1315, 2002     

Bio‐based nanocomposites from functionalized plant oils and layered silicate

Some discovery work was done on the synthesis of clay nanocomposites based on renewable plant oils. Functionalized triglycerides, such as acrylated epoxidized soybean oil, maleinized acrylated epoxidized soybean oil, and soybean oil pentaerythritol maleates, combined with styrene were used as the polymer matrix. The miscibility of these monomers and clay organomodifier was assessed by solubility parameters. The formation of nanocomposites was confirmed by both X‐ray data and transmission electron microscopy. The morphology showed a mix of intercalated and partially exfoliated sheets. The flexural modulus increased 30% at only 4 vol % clay content, but there was no significant effect on flexural strength, glass‐transition temperature, and thermal stability. Property enhancement was related to the degree of exfoliation that depends on both the polarity and flexibility of the monomers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1441–1450, 2004     

Biodiesels from beef tallow/soybean oil/babassu oil blends

The aim of this work is to examine the behaviour of gutta-percha (α–β) after heating, because of the several techniques using the warm gutta-percha as root canal filling material. Samples of gutta-percha have been examined by the thermal analysis. The gutta-percha has been submitted to four runs of heating from the temperature of 25–130 °C, followed by spontaneous cooling. It was found that some products have shown the typical behaviour of the α-gutta-percha; some materials have shown characteristics similar to the conventional β-gutta-percha. The samples have shown a significant mass loss after the first run of heating, while the mass tends to stabilize after the third run. Heating of gutta-percha up to 130 °C causes physical changes; this is due to the presence of additives, which alter the behaviour of the material.     

Development of completely bio‐based epoxy networks derived from epoxidized linseed and castor oil cured with citric acid

Bio‐based epoxy resins were synthesized from nonedible resources like linseed oil and castor oil. Both the oils were epoxidized through in situ method and characterized via Fourier transform infrared and ¹H‐NMR. These epoxidized oils were crosslinked with citric acid without using any catalyst and their properties compared with diglycidyl ether of bisphenol A‐epoxy. The tensile strength and modulus of epoxidized linseed oil (ELO) were found to be more than those of epoxidized castor oil (ECO)‐based network. However, elongation at break of ECO was significantly higher than that of both ELO and epoxy, which reveals its improved flexibility and toughened nature. Thermogravimetric analysis revealed that the thermal degradation of ELO‐based network is similar to that of petro‐based epoxy. Dynamic mechanical analysis revealed moderate storage modulus and broader loss tangent curve of bio‐based epoxies confirming superior damping properties. Bioepoxies exhibit nearly similar contact angle as epoxy and display good chemical resistant. The preparation method does not involve the use of any toxic catalyst and more hazardous solvents, thus being eco‐friendly.     

Miscibility and morphology of poly(ethylhexylacrylate)/liquid crystal blends prepared under different conditions

A comparative study of the phase diagrams and morphology of blends of poly(2‐ethylhexylacrylate) and low molecular weight liquid crystals (LCs) prepared under different conditions is presented. Two LCs are used; one is the 4‐cyano‐4′‐n‐pentyl‐biphenyl and the other is the eutectic mixture of cyanoparaphenylenes known as E7. Two series of blends are prepared under different conditions. The first series is obtained by the polymerization induced phase separation (PIPS) process under UV‐curing starting from a monomeric mixture, while the second series is prepared by a combination of the solvent induced phase separation and the thermally induced phase separation process starting from a mixture containing a commercial polymer with known molecular weight. Using gel permeation chromatography, it is found that the polymer molecular weight of the UV‐cured systems decreases with the concentration of LC in the precursor mixture. The experimentally obtained phase diagrams of these two series of systems show a miscibility shift at the composition where the molar mass of the polymer in the PIPS/UV blend exceeds that of the commercial polymer. Data are rationalized in terms of the Flory‐Huggins theory of isotropic mixing and the Maier‐Saupe theory of nematic order. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 18–27, 2007     

Morphology of reactive PP/PS blends with hyperbranched polymers

To study the efficiency of different mechanism for reactive compatibilization of polypropylene/polystyrene (PP/PS) blends main chain or terminal functionalized PP and terminal functionalized PS have been synthesized by different methods. While the in-situ block and graft copolymer formation results in finer phase morphologies compared to the corresponding non-reactive blends, the morphology development in the ternary blend system PP/PS + HBP (hyperbranched polymer) is a very complex process. HBP with carboxylic acid endgroups reacts preferably with the reactive sites of the oxazoline functionalized PS (PS-Ox) and locates mainly within the dispersed PS-Ox phase. A bimodal size distribution of the PS-Ox particles within the oxazoline modified PP (PP-Ox) matrix phase is observed with big PS-Ox particles (containing the HBP as dispersed phase) and small PS-Ox particles similar in size like the unimodal distributed particles in the non-reactive PP-Ox/PS-Ox blends. Factors influencing the morphology are discussed.     

Thermal investigation of biodiesel blends derived from rapeseed oil

Over the last few years, the production of biodiesel from vegetable oil has significantly increased in Romania due to its obligatory use in the composition of diesel fuel. In this study, biodiesel from rapeseed oil was produced using methanol and a base catalyst. Four samples of biodiesel/diesel blends were prepared for analysis to determine the main thermal decomposition processes and calorimetric events. The thermal profiles were compared to reference diesel. The data obtained on the Thermogravimetry/Differential thermogravimetry and DTA curves show the quality of biodiesel/diesel blends and the possibility that the fuel be used in diesel engines. It was found that biodiesel blends with higher percentage of biodiesel in their compositions were more thermally stable than diesel fuel.     

Studies on polymers and composites from lignin and fiber derived from sugar cane

Sugarcane fiber (i.e. bagasse) lignin has a larger fraction of aromatics unsubstitution in the ortho position than hardwood or softwood lignin and hence has the greater ability to be derivatized. Furthermore, organosolv lignin has a higher purity than sulfonated and kraft lignins. This work examines the purification of organosolv lignin derived from bagasse and the physico‐chemical properties of the lignin and lignin‐phenol formaldehyde (PF) resin coatings, and composites. The wetability tests have shown that lignin and lignin‐PF resin films are effective water barrier coatings, though the contact angles of lignin‐PF resin films were considerably less than the wax films. The overall mechanical properties (i.e. peak stress, peak strain and modulus) of the bagasse fiber composites were lower than the values obtained with the composites without the inclusion of bagasse fiber. Copyright © 2007 John Wiley & Sons, Ltd.     

Carbonyldiimidazole‐accelerated efficient cure of epoxidized soybean oil with dicyandiamide

This study investigates the curing of epoxidized soybean oil (ESO) using dicyandiamide (DICY) and combinations of DICY with several accelerators as curing agents. The differential scanning calorimetry (DSC) results indicated that carbonyldiimidazole (CDI) is a highly efficient accelerator for the ESO‐DICY curing system. CDI accelerated ESO‐DICY curing system can gel within a short period of 13 min at 190 °C. The activation energies of the ESO‐DICY curing systems with and without CDI are 95 and 121 kJ mol^?1, respectively. Similar acceleration effect was observed in the ESO‐diglycidyl ether of biphenyl A (DGEBA) blending formulations. When the molar part of the glycidyl epoxy groups of DGEBA was equal to the internal epoxy groups of ESO in the mixture, gelation of the DICY curing system accelerated by CDI was achieved in 3 min at 160 °C. Furthermore, the DSC results with FTIR analysis suggest that the stoichiometric curing molar ratio was 3 ESO epoxy units per 1 DICY molecule. Two epoxy units reacted with DICY to give secondary alcohols, while the other one linked to the nitrile group. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 375–382     

Thermal and kinetic evaluation of biodiesel derived from soybean oil and higuereta oil

The purpose of this work is to evaluate the thermal and kinetic behavior of biodiesel derived from soybean and higuereta oils. The thermogravimetric profiles of biodiesels indicated one step associated with decomposition of the ethyl esters. The thermal profiles were compared with reference diesel. Kinetic parameters were obtained by thermal analysis, estimating reaction order, pre-exponential factor and activation energy. For estimation of the kinetic parameters the Coats & Redfern method was used. The selection criterion of best fit was based on the correlation coefficient of the linear regression and the compensation effect of the kinetic parameters.     

Fully bio-based thiol-ene photocured thermosets from isosorbide and tung oil

Direct preparation of coatings from neat vegetable oils without any pretreatment or modification is an elegant way of demonstrating the potential of renewable sources and it is also in line with the principles of Green Chemistry. In this work, photocured coatings were prepared from tung oil (TO), hazelnut oil (HN), and isosorbide. First, a dithiol derivative of isosorbide (ISTMP) was synthesized and then mixed with TO, HN, and a cationic photoinitiator. For comparison, formulations were also prepared by using two different commercial thiol compounds. Coating formulations were applied onto glass substrates and cured under UV light where oxidative polymerization and photoinitiated thiol-ene addition reactions took place concomitantly. Double bond conversion percentages, thermal degradation properties, water contact angles, and surface hardness of the coatings were determined. Furthermore, a model reaction between ISTMP and oleic acid was performed to prove that ISTMP reacts with the fatty acid. ISTMP containing formulation displayed a fast initial double bond conversion and its water contact angle value was found as 88 ± 3°. Rigid and thermally stable isosorbide ring improved both the thermal properties and the surface hardness of the coatings.