Pentaerythritol Ester Of Rosin Research Articles

Kinetic Studies of Esterification of Rosin and Pentaerythritol

Esterification of rosin with pentaerythritol produces rosin pentaerythritol ester (RPE) which is widely used in paint, coating, and pressure-sensitive and hot-melt adhesive industries. Although RPE has excellent valuable applications and has been industrially produced, studies on the reaction kinetics have not been widely reported in the present literature. This work proposed a kinetic study of RPE synthesis by including a series of consecutive reactions forming mono-, di-, tri-, and tetra-ester with decarboxylation of rosin as a side reaction in the kinetics model. For esterification, the reaction rates were determined by the second-order kinetic model. The first-order kinetic order was proposed for decarboxylation. Kinetic experiments were performed at a temperature range of 260 °C to 290 °C. The initial molar ratio of pentaerythritol to rosin (in the mole of OH/COOH) used was between 0.8 and 1.2. A small amount of samples were withdrawn in certain time interval. The sample was analyzed to evaluate their acid and saponification number. Afterward, those experimental data were used to simulate and validate the proposed kinetic model. In general, the proposed model could capture the experimental data well. The resulting activation energies ranged from 65.81 to 129.13 kJ mol−1 for esterification and 233.00 kJ mol−1 for decarboxylation. This model also offers a new insight that correlates well with tetra-ester formation and the softening point.

Thermal Stability Evaluation of Resin Acids and Rosin Modified Resins.

Rosin is a sustainable resource, which is mainly composed of resin acid. Rosin-modified resin is widely used in adhesives, inks, coatings, and other fields, and its stability is very important for the production, storage, and use of products. Thermal stability and reactivity of three resin acids (levopimaric acid, neoabietic acid, and dehydroabietic acid) and four rosin-modified resins were studied using an accelerating rate calorimeter (ARC). They are stable, and exothermic reactions do not occur even when they were heated to 200 °C under a nitrogen atmosphere, but they are unstable under an oxygen atmosphere. The mechanism of the oxidation reaction process was found: first, resin acids absorb oxygen, and then an exothermic oxidation occurs. The initial exothermic temperature (T0) of levopimaric acid, neoabietic acid, and dehydroabietic acid are 354.01, 353.83, and 398.20 K, the initial oxidation kinetics shows a second-order reaction, and the activation energies (Ea) are 42.90, 58.05, and 46.60 kJ/mol, respectively. Peroxide concentration of three resin acids were determined by iodometry. The T0 values of hydrogenated rosin, disproportionated rosin, hydrogenated rosin glyceride, and hydrogenated rosin pentaerythritol ester, the four rosin-modified resin, are 353.71, 348.32, 412.85, and 412.44 K. Levopimaric acid and neoabietic acid have higher oxidative reactivity and easily undergoes an oxidation reaction at lower temperature. Rosin-modified resins are stable and find it difficult to undergo oxidation reactions.

Preparation and characterization of carboxymethyl cellulose/poly (ethylene glycol) -rosin pentaerythritolester polymeric nanoparticles: Role of intrinsic viscosity and surface morphology

Polymeric nanoparticles gained importance due to their excellent chemical, physical and biological properties. Herein, novel sonochemical synthesized polymeric nanoparticles were constructed based on carboxymethyl cellulose (CMC)/poly (ethylene glycol) (PEG) polymer blend matrix and rosin pentaerythritolester (RE). Determining the rheology of the novel nanostructure by using dilute solution viscometer (DSV) method was aimed in this paper. This paper was aimed at to determine on the rheology of the novel nanostructure using the dilute solution viscometer (DSV) method.The influence of the temperature, mass ratio, and salt on the intrinsic viscosity of the synthesized CMC/PEG-RE nanoparticles was investigated and its physico-chemical properties were optimized using different mathematical equations such as Huggins, Kraemer, Tanglertpaibul-Rao, Higiro and Rao. The Krigbaum-Wall parameter, Berry number and dimensionless parameter were calculated to understand the degree of miscibility and the synergistic interaction of nanostructures. The Huggins was found to be the most suitable model with the highest correlation constant (R2: 0.94-0.99), and the intrinsic viscosity (22.2-23.4 dl/g). The surface morphology and chemical analysis of the polymeric nanoparticles were evaluated by Fourier-transform infrared spectroscopy (FTIR) and scanning transmission electron microscope (STEM). The results provided a better understanding of RE interactions in CMC/PEG polymer blends and colud be a promising nanocarrier for biomedical applications.

Preparation of Rosin Pentaerythritol Ester Over an Fe3O4-Supported ZnO Catalyst

Conversion of rosin to its pentaerythritol ester provides a means of improving its water resistance, alkali resistance, and oxidation resistance, thereby increasing its stability. Rosin pentaerythritol ester is much more amenable to industrial applications than the parent compound. To overcome the difficulty of catalyst recovery and its associated high cost during the synthesis of rosin pentaerythritol ester, Fe3O4-supported ZnO catalysts, such as Fe3O4@ZnO and Fe3O4@SiO2–ZnO, have been designed and synthesized. The structures, morphologies, and compositions of the materials have been characterized by TEM, XRD, and XPS. The results of esterification reactions demonstrate that Fe3O4@SiO2–ZnO has excellent catalytic performance and stability. The degree of esterification in the production of rosin pentaerythritol ester reached 87.9%, far exceeding the yields attained with other catalysts. Moreover, the catalyst could be reused five times without incurring a loss of activity. The effects of zinc source, zinc loading, and reaction conditions on the esterification have been investigated in detail. This study provides a class of heterogeneous catalysts with excellent properties for the synthesis of rosin pentaerythritol ester. In our paper, the optimum process conditions for obtaining rosin pentaerythritol ester have been identified as zinc nitrate as the zinc source, a theoretical loading of zinc source of 0.45 g, a reaction temperature of 250 °C, a reaction time of 5 h, and a catalyst loading of 0.2 g, when starting from rosin (15 g) and pentaerythritol (1.7 g). The conversion rate was 87.9%, and the acid value was 25.0 mg KOH g−1. This research provides an improved protocol for the rosin esterification reaction.

Pentaerythritol rosin ester as an environmentally friendly multifunctional additive in vegetable oil-based lubricant

Abstract Abietic acid is an abundant renewable natural resource. Pentaerythritol rosin ester (PRE), which is synthesized by esterification of abietic acid and pentaerythritol, is notably environmentally friendly. In our study, we first report PRE as an environmentally friendly multifunctional additive in vegetable oil-based lubricant. The dynamic viscosity, kinematic viscosity, thermal stability and oxidation stability were investigated. The dynamic viscosity of rapeseed oil (RO) and soybean oil (SO) increased by 136.11% and 179.3% at 25 °C when 20 wt% of PRE was added. The viscosity results indicated that PRE can significantly increase the viscosity of RO and SO base oils to expand their range of applications. Moreover, lubricant samples with PRE had higher thermal stability and oxidation stability compared with pure RO and SO. The onset temperature (OT) of oxidation of RO and SO increased by 7.7 °C and 12.6 °C, respectively, when the concentration of PRE was 20 wt%. The oxidation induction time (OIT) of RO and SO increased by 305% and 124%, respectively, when the concentration of PRE was 20 wt%. Therefore, environmentally friendly multifunctional additive of PRE may be a potential alternative to the traditional additives in the preparation of eco-friendly bio-based lubricant.

Characteristics and Kinetics of Rosin Pentaerythritol Ester via Oxidation Process under Ultraviolet Irradiation.

A self-designed reaction device was used as a promising equipment to investigate the oxidation characteristics and kinetics of rosin pentaerythritol ester (RPE) under UV irradiation. Photo-oxidation kinetics and the initial quantum yield (Φ) of RPE were calculated. The initial oxidation product of the photo-oxidation reaction—peroxide was analyzed by iodimetry. The peroxide concentration is related to the light intensity (I) and the temperature (T), and the increasing T and I would destabilize the RPE by accelerating peroxide forming. Photo-oxidation of RPE follows the pseudo first-order reaction kinetics. The relationship between activation energy and logarithm of light intensity (ln I) is linear, and it is expressed as Ea = −4.937ln I + 45.565. Φ was calculated by the photo-oxidation kinetics, and the average value of Φ was 7.19% in the light intensity range of 200–800 μW cm−2. This research can provide fundamental information for application of RPE, and help obtain a better understanding of the stability of rosin esters.

Assessment of the compatibility in hot melts by using different thermoanalytical methods. Ethylene/n-butyl acrylate (EBA) hot melts containing tackifiers of different nature

Several thermoanalytical methods were used to assess the compatibility of EBA (copolymer of ethylene and n-butyl acrylate) hot melts containing tackifiers of different nature (pentaerythritol rosin ester, polyterpene resin, aliphatic hydrocarbon resin, aromatic hydrocarbon resin, and cycloaliphatic-aromatic hydrocarbon resin). The influence of the compatibility of EBA hot melts on their rheological, viscoelastic, and adhesion properties to polar (aluminum foil) and nonpolar (polypropylene film) substrates were analyzed. The viscosity and shear thinning at 160 °C of EBA hot melts varied significantly by changing the tackifier nature; however, at 180 °C all EBA hot melts showed similar viscosities and shear thinning was absent because of the rupture of physical interactions between their components. EBA copolymer showed broad tackifier compatibility, even though aliphatic and aromatic hydrocarbon resins were less compatible. Compatibility was assessed by softening point and cloud point measurement, and dynamical mechanical thermal analysis. The most compatible EBA hot melts were obtained with rosin ester, polyterpene and cycloaliphatic-aromatic hydrocarbon tackifiers and they showed the highest tack and adhesion. On the contrary, the less-compatible EBA hot melts were obtained with aromatic and aliphatic hydrocarbon tackifiers, and they showed the lowest adhesion. EBA containing aliphatic hydrocarbon tackifier was exceptional because of even being incompatible, it showed high tack.

Changes in compatibility, tack and viscoelastic properties of ethylene n-butyl acrylate (EBA) copolymer–pentaerythritol rosin ester blend by adding microcrystalline wax, Fischer–Tropsch wax and mixture of waxes

Ethylene n-butyl acrylate copolymer (EBA) instead of ethylene vinyl acetate copolymer (EVA) can be used as the base polymer for hot melts. The lower polarity of EBA should affect differently the compatibility with the wax and the tackifier as compared to EVA. In this study the compatibility, tack and viscoelastic properties of EBA copolymer–pentaerythritol rosin ester blended with waxes of different nature (Fischer–Tropsch and microcrystalline) and in different amounts were studied.An increase in compatibility of EBA-copolymer blend with microcrystalline wax was produced leading to increased tack and open time, and reduced viscosity. In contrast, the addition of Fischer–Tropsch wax decreased the compatibility and tack of the EBA-copolymer blend. The addition of a mixture of microcrystalline and Fischer–Tropsch wax caused a better balance in the rheological properties and thermal stability of the EBA-copolymer blends. Finally, an increase in the wax mixture content produced a complete removal of tack caused by dilution of the tackifier in the polymer blend rather than by differences in compatibility.

Effects of Different Modified Resin on Physical Stability of Oil Dispersed Pesticides

Cyazofamid-pyraclostrobin( 12. 5%) oil dispersion was prepared by using methyloleate as the dispersing medium. The influence of adding hydrogenated rosin glycerin ester( HRGE),hydrogenated rosin pentaerythritol ester( HRPE) and rosin modified 4-tert-octylphenol resin( RMOR) on the physical stability and rheological behavior of the oil dispersion were investigated,respectively. The results of Fourier transform infrared spectroscopy( FTIR) indicated that the absorption peak of HRGE,HRPE and RMOR disappeared,meanwhile,the absorption peak of ester group was observed compared with rosin. This indicates that the softening point of different resin increases with the extension of carbon chain in their molecular structures.Moreover,the viscosity and the physical stability of the oil dispersion increase( lower oil separation ratio) with the increasing mass fraction of resin. The rheological tests show that the positive thixotropy is observed for the oil suspension prepared with modified resin. However,the oil suspension prepared with different resins significantly differs in the yield value,presented as RMOR HRPE HRGE RA. The physical stability of different oil suspensions exhibits the same tendency. In conclusion,modified resins are capable of serving as the anti-settling agents in the preparation of oil dispersion of pesticides.

Effect of Rosin Ester on Water-Resistant Adhesion Oximized RTV-1 Silicone Rubber Sealant

It is necessary to improve the adhesion of the cured rubber to a substrate as it is used extensively. It is well known that an improvement in adhesion can be realized by incorporating in the composition a sliane or siloxane. Although the composition provides good adhesion to many kinds of substrates, it has been found that the adhesive bond degrades rapidly under wet conditions. To be solved it, rosin eater was incorprated in the silcone ruber in the paper. Increasing the content of rosin ester could induce a relative high adhesion in hot water. Moreover, when the content of modified rosin pentaerythritol ester was above 4.5 phr, the immersion days in hot water before adhesive failure occured were three times than that of non-additive rosin esters.

Properties Controlling the Impact of Styrenic Block Copolymer Based Pressure-Sensitive Adhesives on Paper Recycling

A model was developed for predicting the removal of hot-melt pressure-sensitive adhesives (PSAs) from paper recycling operations via screening using standard adhesive response data. A series of hot-melt PSAs consisting of a styrene−isoprene−styrene/styrene−isoprene linear triblock, diblock copolymer blend, tackifying resin, and naphthenic process oil were blended in combinations to produce a range of properties. The PSAs were formulated with two types of tackifiers, a pentaerythritol ester of rosin and a C5 petroleum hydrocarbon, to provide variation in the formulation composition. The measured removal efficiency versus temperature curves for these PSAs possess a sigmoidal shape, with removal decreasing from 100 to 0% between transitions for the rubbery and polystyrene domains marking significant changes in the mechanical properties. An exponential-based sigmoidal function containing two fitting parameters, inflection temperature and a factor that determines the width of the sigmoid, provided an excellent...

Surface characterization of pentaerythritol rosin ester

Pentaerythritol rosin ester (PERE), which is used as a tackifier in some adhesives, has been characterized by X-ray photoelectron spectroscopy (X.p.s.), secondary ion mass spectrometry (s.i.m.s.) and contact angle measurements. X.p.s. indicates that the surface layer of PERE consists mainly of tri- and tetraester, and many peaks have been assigned in the s.i.m.s. spectra. The surface energy of PERE is quite low which is probably a factor in making it useful as a tackifier.

Preparation and study of release kinetics of rosin pentaerythritol ester microcapsules.

Rosin was esterified with pentaerythritol and intermediate reaction products with different acid values were isolated. Microcapsules containing sulphadiazine were prepared by a solvent evaporation technique using these esters as wall materials. The microcapsules were evaluated for their size, drug content, and release characteristics in simulated gastric and intestinal fluids. The microcapsule size increased as the acid value of the ester decreased. The release of the drug was studied by using first-order, Higuchi and Hixon-Crowell cube root models. The release mechanism of the microcapsules is discussed.

Evaluation of compressibility of pentaestergum coated aspirin microcapsules.

We have earlier reported the usefulness of the pentaerythritol rosin ester (pentaestergum) as a coating material, its dissolution kinetics and in vivo release studies in dogs. The present communication deals with the compressibility of the pentaestergum-coated aspirin microcapsules. The microcapsules were prepared by the pan-coating method described earlier. These were compressed into the tablets using a single punch machine. The tablets were evaluated for hardness, friability loss, disintegration time and dissolution studies. The results showed that there were significant differences in the release characteristics from the microcapsules and the compressed tablets. The effect of 5 per cent starch as a disintegrating agent in the tablet formulation was also studied. The results showed that the tablets can be a suitable dosage form for pentaestergum-coated microcapsules to give a delayed drug release.

Study of rosin and rosin derivatives as coating materials for controlled release of drug

Rosin and rosin derivatives are widely used as film-forming agents in paints and varnishes. Their use as coating materials has been reported. This paper describes the evaluation of rosin derivatives such as rosin pentaerythritol ester, rosin maleic acid adduct esterified with glycerol and pentaerythritol, and abietic acid as coating materials. Salicylic acid granules were coated and evaluated for moisture absorption, flow characteristics and in vitro dissolution studies. It is observed that rosin and pentaerythritol ester impart excellent moisture protection and these can be used for enteric coating and controlled release of drug.

In vivo performance of pentaestergum-coated aspirin microcapsules.

The in vivo study of the pentaestergum-coated aspirin microcapsules was carried out in two healthy female dogs. Blood samples were collected at different time intervals and analysed for total salicylate content. The results were compared with plain aspirin granules. A delayed release of drug was observed from pentaestergumcoated drug microcapsules. Various pharmacokinetic parameters have been calculated and reported. The drug is absorbed from the dosage form and is made available for further therapeutic action at a particular receptor site. This is known as the bioavailability of the drug. The extent of drug absorbed and the rate of absorption are affected by a number of factors dependent upon the physicochemical properties of the drug, its biological properties and patient’s factors. The extent of drug absorption also depends upon the variable nature of the chemical environment throughout the length of the gastrointestinal tract. The extent of bioavailability is usually determined either by measuring the area under the blood concentration-time curve or from cumulative amounts of drug excreted in the urine. These are three parameters describing a blood level curve that are considered to be important in evaluating the bioequivalence of two formulations. These are (1) the peak height concentration, (2) the time of peak concentration and (3) the area under the plasma concentration-time curve. Although many in vitro methods are available and useful, there is no totally satisfactory in vitro substitute for the in viwo determination of drug availability in the evaluation of various dosage forms. We have reported the effect of pH on release characteristics of pentaestergum microcapsules (Pentaerythritol rosin ester) and the dissolution kinetics (Pathak and Dorle 1986). This communication deals with the in vivo evaluation of pentaestergum aspirin microcapsules in bitches. The drug was fed orally to the experimental animals. Blood samples were withdrawn at specified time intervals and analysed for total salicylates in the plasma. On the basis of plasma drug concentration various pharmacokinetic parameters have been studied and are discussed. Pentaestergum aspirin microcapsules were prepared by encapsulating aspirin I .I’. granules using a standard coating technique (Pathak et al. 1985). To study the in vivo performance two healthy bitches (A, 15 kg and B, 16kg) were used as experimental animals. They were fasted for 12 h before drug administration. Pentaestergum aspirin microcapsules were suspended in 20 ml of 5 per cent acacia solution, and 20 mg/kg aspirin dose equivalent microcapsules were administered through a stomach tube. An additional 50 ml of purified water was also given at the

Effect of pH on the release characteristics of pentaestergum microcapsules and a study of dissolution kinetics.

Rosin and rosin esters have excellent film-forming properties. Pentaerythritol-rosin ester (penta-ester gum) is found to be useful as moisture-protecting material with delayed release of drug. This communication relates the effect of pH on the release characteristics of a drug from penta-ester gum coated microcapsules. Salicylic acid granules were encapsulated using a 10 per cent solution of penta-ester gum in acetone. The microcapsules were evaluated for their drug release characteristics. Various pH media (pH 1.2, 3.0, 5.0, 7.2 and 8.0) were used. The results showed that penta-ester gum exhibits excellent resistance to higher pH levels and can be used for the sustained release of the drug. Dissolution rate constants were calculated and they agree with the assumption of Hixson and Crowell's cube-root equation.

Peel adhesion and viscoelasticity of rubber–resin blends

AbstractMixtures in various proportions of natural rubber (NR) and each of two tackifier resins, a poly‐β‐pinene and a modified pentaerythritol rosin ester, were used as the adhesive layer in joining a flexible polyester strip to a plane glass substrate. Measurements of the force required to peel the strip from the glass at a 90° angle were made over a range of pulling rates at several temperatures. Application of time‐temperature superposition enabled a master curve of (reduced) peel force versus (log) pulling rate at a standard temperature (296 K) to be obtained for each adhesive composition. The master curves showed, in increasing order of pulling rate, some or all of four different modes of peeling: (i) peeling with viscous adhesive response, (ii) peeling with rubbery response, (iii) oscillatory or slip‐stick peeling, and (iv) peeling with glassy adhesive response. In general, transitions between the different peeling modes were quite abrupt. Increase in concentration of tackifier resin caused displacement of the master curve toward lower pulling rates [an effect interpreted in terms of an increasing adhesive glass temperature (Tg)], and a superimposed displacement of the transition between peeling modes (i) and (ii) toward higher pulling rates‐an effect attributed to reduction in adhesive average molecular weight. The influence of the tackifier resin in modifying the viscoelastic characteristics of the adhesive was further demonstrated in a comparison of the peel force master curves with corresponding master curves of dynamic storage modulus.