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An organotin copolymer with tin content of 22% was prepared by the reaction of methyl methacrylate and tri‐n‐butyltin methacrylate. The prepared copolymer was incorporated into a paint formulation containing cuprous oxide as an external toxin. Laboratory evaluation of the formulation showed that the average value of the leaching rate of Cu was 7 µg/cm2/day, while the leaching rate of tin was found to be in the range of 0.033 µg/cm2/day. The antifouling performance of the prepared formulation was tested as painted areas on the hull of a trading ship. After about one year's running period through the Mediterranean and Red Sea harbours the tested areas showed good antifouling efficiency compared with the commercial antifouling paint.

To organotin polymer systems were prepared based on the reaction of tri‐n‐butyltin methacrylate with methyl methacrylate ad acrylonitrile. Tin content of the polymers was about 22% and the physical properties of the organotin polymer films were investigated. The anti‐fouling potential of the prepared polymers was investigated as unpigmented and pigmented coatings at Alexandria and Port‐Said. Compositions containing vinyl copolymer as a co‐resin as well as cuprous oxide as a supporting toxin showed good antifouling performance for more than three years.

Two sets of formulations based on three copolymer and three terpolymer systems involving tributyltin methacrylate(BTMA),methyl methacrylate(MMA) and acrylonitrile (AN) with variable tin contents of 7, 15 and 22% were prepared. There is only one varient in each formulation of the six prepared, that is the type of organotin polymer whether it is a copolymer or terpolymer of a definite tin content 7 or 15 or 22%. The binder mixture is a blend consisting of the organotin polymer, a vinyl copolymer and its external plasticizer and little amount of rosin. A moderate and fixed amount of cuprous oxide was introduced into all formulations as a supplementary toxin with organotin polymer. Leaching rates of micro amounts of copper and tin were determined. Panel exposure test in the sea was performed at Port Said. Best antifouling efficiency was obtained from formultions containing organotin copolymer or terpolymer of 22% tin content and that containing organotin copolymer of 15% tin.

Three copolymer and three terpolymer systems involving tributyltin methacrylate, methyl methacrylate and acrylonitrile were prepared with variable tin content of 7, 15 and 22%. The structure of the organotin polymers was investigated by the elemental analysis of tin and nitrogen and by infrared spectroscopy. Long‐term leaching rate determinations of tin from the organotin polymer films were studied and were in the range of 0.033–0.045 ?g Sn/cm2/day. The antifouling performance of the prepared polymer varnishes was tested at Ismailia and at Alexandria. Tributyltin methacrylate‐methyl methacrylate copolymer with tin content of 22% exhibited the highest antifouling potential for more than 18 months.

The effect of pigment filler and extender on the antifouling efficiency of six compositions containing organotin polymer is studied. The binder mixture is a blend containing a copolymer of tri‐n‐butyltin methacrylate and methylmeth acrylate (OTP) with 22% tin content, a vinyl copolymer with its external plasticizer and little amount of rosin. Cuprous oxide was added as a supplementary toxin with the OTP. Leaching rates of microamounts of copper and tin were determined for a period of nearly one year applying standard techniques. Painted plates were immersed in Suez Canal waters at Port‐Said for more than 36 months. Comparison between different fillers and extenders on the antifouling behaviour of painted surfaces is shown. Compositions containing cellite and china clay exhibited the maximum antifouling performance.

To prepare and characterise organotin polymers via a new synthetic route by exchange reactions of poly‐N‐acryloyloxy‐ and poly‐N‐methacryloyloxy‐tetrabromophthalimide with hydroxy‐ and aminotri‐n‐butyltin benzoates.

Preparation of N‐acryloyloxytetrabromophthalimide (NATP) and N‐methacryloyloxytetrabromophthalimide (NMTP) by the reaction of N‐hydroxytetrabromo‐phthalimide with acryloyl or methacryloyl chloride. The exchange reactions of the resulting polymers with amino and hydroxytri‐n‐butyltin benzoate were carried out. The structure of the resulting compounds was characterised.

NATP and NMTP were prepared by the reaction of N‐hydroxy‐tetrabromophthalimide with acryloyl or methacryloyl chloride in the presence of TEA. The monomers prepared were easily polymerised. The exchange reactions of poly‐NATP and poly‐NMTP with amino and hydroxytri‐n‐butyltin benzoate were studied. The structure of the polymers and copolymers prepared was confirmed by tin analysis, IR and ¹HNR spectroscopy.

The new monomer described in the present investigation may be useful for the preparation of organotin polymers by a new synthetic route. Also, the organotin polymers prepared had good film properties and were suitable for film formation.

The method for the preparation of monomer is simple and the exchange reactions provide a simple and practical solution for preparation of some classes of organotin polymers and copolymers.

The method of preparation of organotin polymers was novel and may be useful for preparation of other organotin polymers and copolymers.

Preparation of new organotin polymers via a new synthetic route based on the exchange reactions of pentachlorophenyl acrylate or methacrylate with amino‐tri‐phenyltin benzoates or hydroxyl‐tri‐phenyltin benzoates.

The pentachlorophenyl acrylate or methacrylate was prepared by polymerisation in solution with azobisisobutyrontrile as a free radical initiator. The polymers obtained were allowed to undergo exchange reactions with amino‐tri‐phenyltin benzoates or hydroxyl‐tri‐phenyltin benzoates. The structure of the polymers prepared was confirmed by IR spectroscopy. Films were prepared from purified organotin polymers solution on glass, PVC and tin plates. The release of tin compound from the films, when immersed in aqueous media, was assessed. The concentration of the released tin (ppm) was measured by atomic adsorption spectrophotometer.

The new synthetic route was effective, the organotin polymers prepared had good film properties and the release of tin compounds increased with the content of tin in the organotin polymers.

The alkaline resistance of the polymeric films prepared needs improvement.

The polymers prepared provide a family of effective polymeric fungicide useful for a number of applications including water sterilisation.

The polymers prepared contained pendent triphenyltin moieties which slowly hydrolysed to give fungicidal and antifouling effects.

Aims to prepare some organotin polymers based on N‐substituted acrylamide and methylacrylamide acid esters via a new synthetic route. Tri‐n‐butyltin‐∝‐bromoacrylate monomer (TBTBA) was prepared and polymerisation carried out. Organotin polymers were prepared via the new synthetic route by exchange reactions.

To determine the optimal general condition for the synthesis and polymerisation of 2‐(N‐phthalimido)ethyl acrylate (NPEA), as well as the exchange reactions of poly‐NPEA with aminated and hydroxylated compounds as a model compound.

Preparation of 2‐(N‐phthalimido)ethyl acrylate by the reaction of N‐(2‐hydroxyethyl) phthalimide with acrylic acid and polymerisation of the resulting monomer. The exchange reactions of the resulting polymer with amines and hydroxy compounds were carried out. The structure of the resulting compounds were characterised.

NPEA was prepared by the reaction of N‐(hydroxyethyl)phthalimide with acrylic acid. The monomer prepared was easily polymerised. The reactions of the resulting polymer with amines and hydroxy compounds were studied. In all cases, the exchange reactions were almost practically quantitative, which was confirmed by elemental analysis, IR and ¹HNMR spectroscopy. Also, it was clear that poly‐NPEA showed a good behaviour as a model compound for a long active polymeric‐drug.

The new monomer described in the present investigation may be useful for the preparation of polymeric‐drug adducts. Also, similar monomeric phthalimides may be synthesised starting from a number of other hydroxy or amino acids, thus providing wider possibilities for the synthesis of pharmacologically active polymers.

The method for preparation of monomer is simple and the exchange reactions provide a simple and practical solution to prepare some classes of macromolecular drugs.

The method of preparation of polymers was novel and may be useful for preparation of polymeric‐drug adducts.

This paper introduces an audio encryption algorithm based on permutation of audio samples using discrete modified Henon map followed by substitution operation with keystream generated from the modified Lorenz-Hyperchaotic system. In this work, the audio file is initially compressed by Fast Walsh Hadamard Transform (FWHT) for removing the residual intelligibility in the transform domain. The resulting file is then encrypted in two phases. In the first phase permutation operation is carried out using modified discrete Henon map to weaken the correlation between adjacent samples. In the second phase it utilizes modified-Lorenz hyperchaotic system for substitution operation to fill the silent periods within the speech conversation. Dynamic keystream generation mechanism is also introduced to enhance the correlation between plaintext and encrypted text. Various quality metrics analysis such as correlation, signal to noise ratio (SNR), differential attacks, spectral entropy, histogram analysis, keyspace and key sensitivity are carried out to evaluate the quality of the proposed algorithm. The simulation results and numerical analyses demonstrate that the proposed algorithm has excellent security performance and robust against various cryptographic attacks.