Poly Butyl Acrylate Research Articles

Internal stress of epoxy resin modified with acrylic polymers produced by in situ UV radiation polymerization

AbstractA cured epoxy resin is modified with polybutyl acrylate (A) and polyethyl acrylate (B) produced by in situ ultraviolet radiation polymerizations of their corresponding monomers in the epoxy resin, respectively, to reduce the internal stress. In the A system, a heterogeneous structure with submicron domains was formed. In the B system, however, the B mixed well with the epoxy matrix. In both systems, the internal stress was decreased by the modification. The glass transition temperature of the epoxy matrix decreased in the B system more than in the A system. The A‐modified resin was superior to the B‐modified resin in reducing the internal stress without decreasing the thermal resistance of epoxy resin.

Termination rate constant in butyl acrylate batch emulsion polymerization

The kinetics of seeded batch emulsion polymerization of n-butyl acrylate (BA) have been investigated at 50°C using potassium persulfate (KPS) as the thermal initiator. The variations in the average number of radicals per particle (n) and termination rate constant (kt) have been determined as a function of conversion for particles of different sizes using established kinetic equations. Contrary to expectations, the values of n were found to be unusually high and the values of kt were found to be very low for all the reactions studied. The high values of n are consistent with the low rates of termination. An explanation has been proposed for the low values of kt based on preliminary computations of the energy barrier for rotation about the terminal C-C bond of the polymer chain end of polybutyl acrylate (PBA).

Study of the polymer latex coalescence by dielectric measurements at microwave frequency?feasibility of the method

The measurement of the complex dielectric constant (e*=e′−je″) in the dipolar absorption domain of the “free” water molecule (microwave region) permits us to follow quasi-specifically and precisely the water circulation during the coalescence process of a latex. Weight losses and dielectric constants variations have been simultaneously recorded upon latex drying, in a resonant cavity at 5 and 9 GHz and under controlled atmosphere and temperature. Two different latexes were studied (polybutylacrylate (PBuA) and polystyrene (PS)) from which the glass transition temperature effect was investigated. It is found that the harder the polymer particles, the more clearly evidenced the flocculation and packing points are. This method appears to be quite reliable for discriminating the various steps in the film formation process of latexes.

Proton magnetic relaxation of slightly crosslinked polybutyl acrylate

Small-scale intramolecular mobility of polybutyl acrylate crosslinked with allyl methacrylate has been investigated by the proton magnetic relaxation method. The mobility of units located next to crosslinks is more inhibited and is characterised by a wider correlation time spectrum compared with that of remote units. About ∼0·2 mole% of the units form fluctuational type contacts with lifetimes of the same order (or longer) than the spin-spin relaxation time. The number of these contacts in the crosslinked polymer is proportional to the degree of crosslinking, while about one-half of the long-lived crosslinks are eliminated during swelling of the polymer. Only about 6 mole % of the crosslinking agent from effective interchain crosslinks.

Ionomers made from copolymers with uniform grafts

Carboxylic acid-containing graft copolymers with uniform polystyrene grafts were synthesized by copolymerization of methacrylate-terminated polystyrene macromers, acrylic acid and butyl scrylate. The graft copolymers were neutralized with metal ions in solution or in melt to form ionomers, which were characterized by IR, TEM and dynamic mechanical analysis. TEM photographs showed that there appeared three phases in the ionomers, namely polystyrene domains, ion clusters and continueous phase of polybutyl acrylate, while dynamic mechanical analysis indicated the phase separation of polystyrene and ion-containing polyacrylate.

Structure and mechanical properties of polymer composites based on isotactic polypropylene prepared by in situ polymerization and study of their structure

The method of in situ polymerization was used to prepare polymer composites based on isotactic PP, PS, polybutyl acrylate or PMMA. The composites were subjected to X-ray analysis. Molecular orientation acquired by PP is preserved intact in presence of the second polymer component. The latter exists in the composite in the form of thin fibrillar aggregates oriented horizontal to the PP stretching axis. Despite thermodynamic incompatibility these composites have very good mechanical properties owing to the high degree of dispersity of the components. The annealing temperature has a marked influence on mechanical properties of the composites, as does crosslinking of the second component.

Unperturbed Dimension of Polymer Molecules from Viscosity Measurements in Different Solvents

Abstract An expression for the determination of the cross-over point concentration, CX, of the polymer in a number of solvents has been derived, and an expression relating Cx with the unperturbed dimension of polymer molecules (r0 2)½ has been proposed. The unperturbed dimensions for polymethyl acrylate, polyethyl acrylate, polybutyl acrylate, polyacrylonitrile, and polyvinyl pyrrolidone have been calculated.

Demonstration of the radical character of the mechanism of the thermal decomposition of polyacrylates

1. Additions of dicumyl peroxide and the tert-butyl ester ofΒ-(triethylsilyl) perpropionic acid accelerate the thermal decomposition of polymethyl methacrylate and polybutyl acrylate. 2. Methane, dimethylphenylcarbinol, and (C2H5)4Si were identified in the decomposition products of polyacrylates in the presence of peroxides, indicating stripping of a hydrogen by the peroxide radicals from the polymer molecules. 3. The data obtained confirm the free radical character of the mechanism of the thermal decomposition of polyacrylates.

Investigation of the mechanical properties of graft copolymers of gelatin with synthetic polymers and their mixtures

A study was made of the mechanical properties of graft copolymers of gelatin with polyacrylonitrile (PAN) and with polybutylacrylate (PBAC), and these were compared with those of pure gelatin. The experimental results show that the elasticity of the system is increased by grafting of the flexible chain PBAC, while the grafting of PAN leads to increased rigidity. For graft copolymers of gelatin with PBAC it was found that shrinkage in the course of heating to 120° is greatly reduced, and this reduction is attributed to the formation of a microheterogeneous structure, the disperse phase of the latter including gelatin and PBAC in its composition. Model mechanical mixtures consisting of these components with approximately the same degree of dispersion of PBAC show shrinkage behaviour during heating to 120° resembling that of pure gelatin.

Pyrolysis-gas chromatography of polybutylacrylate and butylacrylate-acrylonitrile copolymers

The degradation mechanisms of polybutylacrylate (PBA) under the various pyrolysis temperatures were studied by means of pyrolysis-gas chromatography. When the degradation of PBA is performed at the pyrolysis temperature of 530°C or below it, a little yield of monomer (butylacrylate) was observed in addition to the hydrocarbons and acrylic acid which were formed from the competitive reactions of chain scissions and elimination of butene. Observing the relationship between relative yield of products and pyrolysis temperature from PBA, it was suggested that the mechanisms of the thermal degradation of PBA vary with the pyrolysis temperature used. And also we discussed the analysis of butylacrylate-acrylonitrile copolymers by use of the relative yield of the acrylic acid and acrylonitrile.

Plasticization of cellulose triacetate by grafting polybutylacrylate

EARLIER publications on the plasticization of cellulose and its esters by grafting polymethylacrylate (PMA), polybutylacrylate (PBA) and polymethylmethacrylate, are [1-5]. I t was found that, in graft copolymerization conducted under conditions where the original polymer showed considerable swelling, if a flexible chain high molecular weight compound compatible with it were grafted (the system cellulose nitrate-PMA), the molecular-chemical mechanism of plasticization obtained [1]. Due to the affinity between the graft copolymer and the original monomer, when cellulose is plasticized by graft copolymerization with PMA or PBA, the possibility of the monomer diffusing inside the supramolecular structures o f the cellulose is retained, and plasticization occurs on the molecular level [3]. When cellulose triacetates (TAC) are plasticized by grafting PMA, which has limited compatibility with them, the process also takes place on the molecular level, but for mechanical mixes, the structural-molecular mechanism of plasticization obtains [4]. We decided it would be very interesting to study the plasticization of a rigid chain polymer by graft copolymefization with an incompatible flexible chain polymer. For the studies we used the plasticization of cellulose triacetate by grafting PBA. Synthesis of graft copolymers. Synthesis of graft copolymers of cellulose triacetates with PBA was by acetylation of already synthesized graft copolymers of celullose. The starting cellulose material was cotton fluff (polymerization coefficient 1000). The graft copolymers were synthesized in an aqueous emulsion of the monomer using the salt Ce+4 as described in [6]. The acetylation was performed in a homogeneous medium (catalyst HCtO,). I t is important to note that the acetylation of graft copolymers is much more rapid than that of the original cellulose material, due, apparently, to the looser packing of the cellulose contained in the graft copolymer. The result of esterification was a solution of the graft copolymer in the acetylating mixture.

Plasticizing cellulose by grafting polymethyl and polybutyl acrylate

Plasticizing cellulose by grafting polymethyl and polybutyl acrylate

Specific refractivity‐temperature data for polyvinyl acetate and polybutyl acrylate

AbstractRefractive index‐temperature and volume‐temperature data for polyvinyl acetate and polybutyl acrylate have been determined and used to calculate the specific refractivity as a function of temperature by the Lorentz‐Lorentz and the Eyckman equations. The results show a variation of specific refractivity with temperature which exceeds experimental error. The variation is evident as an increase of specific refractivity with temperature above Tm and suggests experiments which will show the increase more clearly. A theoretical justification for the increase of specific refractivity with temperature in polymers is discussed.