Grafted Poly Methyl Methacrylate Research Articles

Book review

A new type of solution-processable graphene coating has been synthesized by grafting polymethylmethacrylate (PMMA) brushes on graphene oxide (GO) via surface-initiated atom transfer radical polymerization (ATRP). One major finding is that the PMMA-grafted GO nanocomposite exhibits synergistic properties of both building blocks, i.e., permeation inhibition of GO and solubility of PMMA in a variety of solvents, which makes it compatible with commonly used coating methods to form uniform coatings with controlled thickness. Our results demonstrate that PMMA-grafted GO coating can effectively block charge transfer at the metal–electrolyte interface and prevent corrosion of the copper substrate under aggressive saline conditions.

Graft copolymers of propylene with styrene and methylmethacrylate: Structure, crystallization and thermal behaviour

Nuclear magnetic resonance spectroscopy (NMR), differential scanning calorimetry (DSC), wide and small angle X-ray scattering (WAXS and SAXS) investigation have been used in order to achieve a molecular, thermal and structural characterization of a sample of propylene-butadiene copolymer containing 3% (wt/wt) of butadiene (uPP) and of uPP samples modified by grafting polymethylmethacrylate (upp-g-PMMA) and polystyrene (uPP-g-PS). The uPP copolymer was synthesized by Himont according to method patented by Himont [1], that allows, by means of the use of a proper catalyst system, co-polymers of propylene with diene having conjugated double bonds in which at least 20% of the unsaturations is of the vinyl type to be obtained. The influence of concentration, distribution and type of the uncrystallizable comonomer units on the thermal behaviour of such co-polymers and on the kinetic, morphologic and thermodynamic parameters related to crystallization process from melt have been also investigated.

The Assessment of Homogeneous Grafting of Cellulose Nitrate

Abstract The homogeneous grafting of polymethyl methacrylate onto cellulose nitrate has been assessed by the techniques of spectroscopy and microscopy combined with chemical procedures. FTIR spectroscopic and electron microscopic evidence confirmed the existence of a true graft copolymer. Homogeneous grafting took place in both the surface layer and the interior of the supermolecular structure of cellulose nitrate. X-ray diffraction provided further evidence that the grafting reaction also occurred in certain ordered domains of cellulose substrate. It is suggested that the free radical graft copolymerization for cellulose nitrate could be performed via a mechanism of denitration and enolization rather than dehydrogenation.

Copolymerization of Polymethyl Methacrylate Macromers withn-Butyl Acrylate and Mechanical Properties of the Graft Copolymers

Abstract The copolymerization of polymethyl methacrylate (PMMA) macromer with butyl acrylate in benzene was studied. the PMMA macromer was obtained by radical polymerization in the presence of thioglycollic acid as a chain transfer agent, followed by termination with glycidyl methacrylate. the copolymerization rate and effects of various copolymerization conditions, such as molecular weight of macromer, charging ratio of macromer to monomer, amount of initiator, kind of solvent, concentration, and copolymerization temperature, on grafting efficiency and molecular weight of copolymer were investigated. the copolymers were purified by fractional precipitation. the purified copolymers with uniform PMMA grafts were characterized by GPC, IR, UV, and DSC. Structural parameters of the copolymers were determined by VPO and membrane osmometry. Average grafting number per chain decreases with an increase of conversion. Measurement of mechanical properties of the copolymers shows that both molecular weight and the c...

Effect of the grafted phase on the radiation-induced graft post-polymerization of acrylonitrile, methyl methacrylate, and acrylic acid onto polypropylene fibres

The heats of sorption, the Henry constants, and the coefficients of diffusion of acrylonitrile, methyl methacrylate, and acrylic acid when sorbed on polypropylene fibres on grafted polyacrylonitrile, polymethyl methacrylate, and acrylic acid are determined. At comparatively low rates of grafting at 40°C the grafted polyacrylonitrile is equally distributed along the polypropylene fibre, while the grafted polymethyl methacrylate and polyacrylic acid are concentrated in a thin surface layer of depth 1–2 μm. The rate of radical graft post-polymerization of acrylonitrile and methyl methacrylate on polypropylene fibre is described by a first order equation with respect to the monomer.

Grafting behavior of copolymers of styrene and ortho‐vinylbenzaldehyde

AbstractStatistical copolymers of styrene and ortho‐vinylbenzaldehyde (o‐VBA) have been prepared by free radical solution polymerization using azodiisobutyronitrile initiator. Subsequent “grafting from” reactions could be induced through photolytic excitation of the pendant aldehyde carbonyl functionality in the presence of methyl methacrylate monomer; however, actual grafting of polymethylmethacrylate (PMMA) to the copolymer backbone was shown to be quite low (< 6% graft‐on). Another more promising route involved abstraction of labile benzylic hydrogens of the copolymer by chemical methods [e.g., dibenzoyl peroxide or α,α′‐di‐(t‐butylperoxy)diisopropylbenzene] to produce potential graft sites. Graft copolymers prepared by this procedure had PMMA content ranging up to about 30% (by weight), depending upon polymerization conditions. Higher grafting levels were generally observed with increasing reaction temperature and prolonged reaction times. While some grafting evidently originated from the copolymer backbone, the presence of the o‐VBA moiety significantly enhanced the ultimate percent grafting. The resulting multicomponent polymer systems displayed substantial miscibility as evidenced by the transparency of their cast films as well as by their glass transition behavior.

Ultralow dose effects in ion-beam induced grafting of polymethylmethacrylate (PMMA)

We have investigated the process of image enhancement in high resolution lithography through polymer grafting techniques. Sensitivity gains of 10 3 –10 4 were obtained for H + , X-ray, e-beam and deep-UV irradiations. Ultralow dose effects in 60 keV H + irradiated PMMA have been observed through the use of the acrylic acid (AA) monomer grafting with irradiated PMMA. At conventional doses of 10 10 cm −2 an inner structure of each feature is revealed. At doses of (1–2) X 10 9 cm −2 , discrete events within the exposed regions are observable. This is the first time that individual events have been observable in a lithography process and sets the upper limit in the useful sensitivity of the resist and ion lithography process. This effect is directly observable only with ions, because of their higher efficiency per particle than either photons or electrons.

Radiation induced graft copolymerization of methyl methacrylate onto chrome-tanned pig skins

Graft copolymerization of methyl methacrylate (MMA) onto chrome-tanned pig skins was carried out by the irradiation with 60Co ▪-rays. The grafted polymethyl methacrylate (PMMA) chains were isolated by acid hydrolysis of the collagen backbone in order to characterize the graft copolymers. Proof of grafting was obtained through the detection of amino acid endgroups in the isolated grafts by reaction with ninhydrin. The grafting yield of MMA in aqueous emulsion was found to be higher than that for pure MMA and MMA in acetone. The degree of grafting increases with increasing monomer concentration in emulsion and reaches maximum at radiation dose ca 15 kGy. The yield of grafting is very high - ca 90% of monomer converts into copolymer and only 10% is converted into homopolymer. The present paper reports the physical properties of chrome-tanned pig skins after graft polymerization with MMA in emulsion. Modified leathers are more resistant against water absorption and abrasion in comparison with unmodified ones. They have more uniform structure over the whole surface, greater thickness and stiffness. The results reported seem to indicate that MMA may be used in the production of shoe upper and sole leathers. The mechanism of some of the processes occuring during radiation grafting of MMA in water emulsion on tanned leathers has been also suggested and discussed.

Mechanism of graft copolymerization of vinyl monomers with silk fibroin

In order to examine the mechanism of graft copolymerization to silk fibroin, polymethylmethacrylate (PMMA) was synthesized using model systems of amino acid-ferrous iron-hydrogen peroxide. It was shown that the phenol OH group of tyrosine and the indole NH group of tryptophan are the most active in chain transfer. The presence of amino acid residues in graft PMMA was established by IR spectroscopy.

Structure of solution grafted polybutadiene

AbstractThree different polybutadienes possessing widely different vinyl and cis monomer structures have been grafted with methyl methacrylate in solution using both benzoyl peroxide and azobisisobutyronitrile catalysts. Careful fractionation and backbone degradation techniques together with molecular weight determinations lead to the conclusions that both catalysts gave graft copolymer in the 10% rubber solutions used. Benzoyl peroxide always gave better graft efficiencies, (as did high vinyl and to a lesser extent high cis polybutadiene). The molecular weight of the polymethylmethacrylate grafts are slightly lower than those of homopolymers polymerized under the same conditions indicating < 20% grafting by chain transfer and termination mainly by disproportionation.