Search

Biodegradable and edible cassava starch-glycerol based films with different concentrations of yerba mate extract (0, 5 and 20wt.%) were prepared by casting. The plasticizing effect of yerba mate extract when it was incorporated into the matrix as an antioxidant was investigated. Thermal degradation and biodegradability of the obtained biofilms were also studied. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), attenuated total reflectance Fourier transform infrared spectroscopy (ATR/FTIR), X-ray diffraction analysis (XRD), water absorbance, stability in different solutions and biodegradability studies were performed. The clear correlation among the results obtained from the different analysis confirmed the plasticizing effect of yerba mate extract on the starch-glycerol matrix. Also, the extract led to a decrease in the degradation time of the films in soil ensuring their complete biodegradability before two weeks and to films stability in acidic and alkaline media. The plasticizing effect of yerba mate extract makes it an attractive additive for starch films which will be used as packaging or coating; and its contribution to an earlier biodegradability will contribute to waste reduction., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

In this paper, we synthesized a kind of bio-based plasticizer epoxidized linoleic acid cardanol ester (ELCE) from cardanol and linoleic acid. Its chemical structure was characterized with FT-IR and 1H NMR. Polyvinyl chloride (PVC) blends plasticized with ELCE were prepared via thermoplastic blending with torque rheometer. The performance including torque, mechanical property, thermal stability, plasticizing property and migration resistance of plasticized PVC blends were investigated and compared with plasticized PVC blends with commercial plasticizer dioctyl phthalate (DOP). The results showed that ELCE improved thermal stability of PVC blends. ELCE played more excellent plasticizing effect on PVC blends than DOP. The better solvent extraction resistance and volatile resistance of ELCE make it possible to completely replace DOP in PVC products. [ABSTRACT FROM AUTHOR]

The requirement of developing energetic binders with suitable energetic plasticizers is to enhance the mechanical properties and to reduce glass transition temperature of propellant and explosive formulations. Compatibility of energetic plasticizer 2,4-dinitro-2,4-diazapentane (DNDA-5) with four different energetic binders viz. poly glycidyl nitrate (PGN), poly(3-nitratomethyl-3-methyloxetane) (PLN), glycidyl azide polymer (GAP) and tetra functional glycidyl azide polymer (t-GAP) was studied by using differential scanning calorimeter (DSC) and density functional theory (DFT) methods. Results obtained for the pure binder was compared with the results obtained for binder/plasticizer blend in the parameters of decomposition temperature and the format of the peak which indicated the compatibility or incompatibility of DNDA-5 with the studied binders. Glass transition temperatures of all these blends were determined by low temperature DSC and showed desirable lowering of glass transition temperature with single peak in the case of PLN. The proposed energetic plasticizer DNDA-5 has displayed its compatibility with three binders PGN, PLN and GAP employing thermal techniques. DNDA-5 has been found as incompatible when it is mixed with t-GAP. The predicted relative trend of interaction energies between plasticizer and binder has provided concurrence to results drawn from thermal studies. [ABSTRACT FROM AUTHOR]

Azido‐terminated hyperbranched multi‐arm copolymer (POGA) with hyperbranched polyether core (PEHO‐c) and linear azido‐terminated glycidyl azide polymer arms (GAPA‐a) has been prepared. The structures of the polymers were characterized by FT‐IR, NMR, GPC and elemental analysis. The molecular weight of POGA was up to ca 17000 g mol−1, far higher than that of common plasticizers (200∼1000 g mol−1). The enthalpy of formation and high nitrogen content of POGA demonstrated its remarkable energy level, and low impact and friction sensitivities indicated its good safety performance in mechanical stimuli. The results of the kinetic and thermodynamic parameters, calculated from non‐isothermal DSC, denoted a fine thermal stability of POGA. Furthermore, the plasticizing effect of POGA, evaluated by plasticizer efficiency and viscosity, was superior to A3 but inferior to Bu‐NENA, however, its exudation was much slower than that of small molecular plasticizers, especially Bu‐NENA. Moreover, the plasticizing mechanism of POGA as energetic macromolecular plasticizer was established by analyzing its structure and performance characteristics. [ABSTRACT FROM AUTHOR]

• The change of Tg value of PMMA with the interaction with DBM. • The amount of decrease in Tg is proven by both DSC analysis and DFT calculations. • DFT computations supported the experimental test. • The importance of chemical reactivity in polymer modifications was explained. In this study, the amount of change in the glass transition temperature (Tg) of PMMA was analyzed by DSC by adding different ratios of dibutyl maleate (DBM) plasticizer to polymethyl methacrylate (PMMA), which is used as the main ingredient of prosthetics in dentistry. For this, liquid DBM was added to powdered PMMA at a rate of 2, 5, 8 and 15 % by mass, and polymerization was carried out at 100 °C. Mechanical tests such as impact resistance, transverse resistance and maximum flexion tests were applied to these prepared mixtures. It was observed that there was a significant parallelism between the Tg values calculated from the DSC curves and the mechanical tests. The Tg value of PMMA was reduced by approximately half with the addition of DBM plasticizer. Additionally, the chemical interaction between PMMA and DBM was analyzed in the light of the Density Functional Theory (DFT) calculations. The binding energy for the mentioned interaction was determined as 1.591 eV. After both species interacted with each other, the glass transition temperature of the formed complex system was theoretically also predicted through the quantitative structure-property relationship (QSPR) model. For theoretical prediction of Tg, the molecular traceless quadrupole moment Θ and the molecular average hexadecapole moment Φ, are used. The change determined as experimental in glass transition temperature as a result of the interaction between PMMA and DBM was supported with theoretical calculations. Experimental and theoretical data are in good agreement. [ABSTRACT FROM AUTHOR]

The development of energetic binders with suitable energetic plasticizers is required to enhance the mechanical properties and to reduce the glass transition temperature of propellant and explosive formulations. The compatibility of the energetic binder poly(3-nitratomethyl-3-methyloxetane) (polyNIMMO) with five different energetic plasticizers viz. bis(2,2-dinitro propyl)acetal (BDNPA), dinitro-diaza-alkanes (DNDA-57), 1,2,4-butanetriol trinitrate (BTTN), N- N-butyl- N'(2-nitroxy-ethyl) nitramine (BuNENA) and diethyleneglycoldinitrate (DEGDN) was studied by differential scanning calorimetry (DSC), rheology, and DFT methods. The results obtained for the pure binder were compared with the results obtained for the binder/plasticizer blend in regard of the decomposition temperature and the format of the peak indicated the compatibility of polyNIMMO with the plasticizers. The glass transition temperatures of the blends were determined by low temperature DSC and showed desirable lowering of glass transition temperature with single peak. The rheological evaluation revealed that the viscosity of the binder is considerably lowered by means of flow behavior upon addition of 20 % (w/w) plasticizer. The addition of BuNENA and DEGDN has maximum effect on the lowering of viscosity of polyNIMMO. The predicted relative trend of interaction energies between plasticizer and binder is well correlated with the corresponding trend of viscosity of binder/plasticizer blends. These experimental studies verified by theoretical methods are valuable to design practical blends of new plasticizers and binders. [ABSTRACT FROM AUTHOR]

Abstract: The degree of gelatinization (DG) of potato starch after treatment with scCO2 was investigated. A broad range of experimental conditions were applied, including variations in temperature (50–90°C), pressure (0.1–25MPa), and the starch water content (16.2–40%wt/wt). Changes in the DG were observed by in situ FT-IR measurements, DSC and confirmed by the XRD analysis. The DG increases at higher temperatures and pressures. A maximum DG of about 14% was achieved at the highest pressure (25MPa) and temperature in the range (90°C). A series of experiments under N2 pressure confirms that scCO2 plays a special role in the gelatinization process. [Copyright &y& Elsevier]

Liquid isoprene rubber (LIR) is commonly used as plasticizer in rubber processing industry. It shows poor compatibility with inorganic fillers. Herein, cardanol grafted onto LIR (CA- g -LIR) was synthesized by solvent-free method and used as the dispersed matrix of silica particles. Results show that the optimum reactive condition is that 7 phr of cardanol monomer and 0.2 wt % of 2, 2-Azobisisobutyronitrile (AIBN) initiator per 100 g LIR react for 12 h at 70 °C. At these conditions, grafting ratio is 6.01%. CA- g -LIR shows obvious plasticizing effect, as is certified by its far high elongation at break (increase of 800%), decreased viscosity (reduction of 62%) and glass transition temperature (T g , decline of 5.0 °C) compared with LIR. Moreover, CA- g -LIR shows good interfacial performance. The dispersion of silica particles in CA- g -LIR is better than that in LIR. CA- g -LIR is obtained by a simple and green way, low-cost, easy for industrial production. It is expected to be acted as plasticizer and compatibilizer at the same time in rubber industry. [Display omitted] • Cardanol grafted onto liquid isoprene rubber obtained by solvent-free method. • Increasing plasticizing effect originated from alkyl flexibility of cardanol. • Interfacial action of SiO 2 reinforced rubber increased by phenolic hydroxyl groups. • Versatile CA- g -LIR is expected in industrial application by produced in batch. [ABSTRACT FROM AUTHOR]

Biobased plasticizers for polymers is a necessity to replace conventional phthalates based plasticizers. In the present study, Citrullus lanatus seed oil (ECLO) was epoxidized in a magnetically stirred reactor. Polyvinyl chloride (PVC) films were synthesized using different concentrations of ECLO. At 40% of ECLO, films showed better surface morphology and exhibited maximum strength and elongation at break. Plasticized PVC film shown tensile strength of 18.6 MPa and elongation at break of 136.18%. No migration was observed in water, designating hydrophobic characteristics of the films. In gasoline, acid (Acetic acid) and alkali (Sodium hydroxide), plasticized samples exhibited a low resistance for migration. X-ray diffraction analysis confirmed no change in crystallinity of PVC after addition of ECLO. Thermogravimetric analysis presented the plasticized PVC films are thermally stable. Differential scanning calorimetry established the plasticizing effect of ECLO as a glass transition temperature (T g) of plasticized films was shifted to a lower temperature.Furthermore, Fourier transform infrared spectroscopy revealed interaction of ECLO with PVC as peaks of C–Cl bond (833 cm−1) and C O stretch (1739 cm−1) were detected. Thus, the present study delivered a better substitute for phthalates as it endorses the application of ECLO in the PVC blend as a plasticizer. • Citrullus lanatus seed oil was epoxidized in a magnetically stirred reactor. • PVC films were prepared of various concentrations of ECLO. • PVC films containing 40% of ECLO exhibited efficient mechanical properties. • Synthesized PVC films were analyzed by SEM, XRD, DTG and TGA, DSC, and FTIR. • PVC ECLO 40 films were exhibited better plasticizing effect and thermal stability. [ABSTRACT FROM AUTHOR]

The main purpose of this paper was to evaluate the impact of both high- and low-Tg polymer additives on the physical stability of an amorphous drug, sildenafil (SIL). The molecular mobility of neat amorphous SIL was strongly affected by the polymeric excipients used (Kollidon VA64 (KVA) and poly(vinylacetate) (PVAc)). The addition of KVA slowed down the molecular dynamics of amorphous SIL (antiplasticizing effect), however, the addition of PVAc accelerated the molecular motions of the neat drug (plasticizing effect). Therefore, in order to properly assess the effect of the polymer on the physical stability of SIL, the amorphous samples at both: isothermal (at constant temperature—353 K) and isochronal (at constant relaxation time—τα = 1.5 ms) conditions were compared. Our studies showed that KVA suppressed the recrystallization of amorphous SIL more efficiently than PVAc. KVA improved the physical stability of the amorphous drug, regardless of the chosen concentration. On the other hand, in the case of PVAc, a low polymer content (i.e., 25 wt.%) destabilized amorphous SIL, when stored at 353 K. Nevertheless, at high concentrations of this excipient (i.e., 75 wt.%), its effect on the amorphous pharmaceutical seemed to be the opposite. Therefore, above a certain concentration, the PVAc presence no longer accelerates the SIL recrystallization process, but inhibits it. [ABSTRACT FROM AUTHOR]