Dibutyltin Maleate Research Articles

Dibutyltin(IV) maleate as a new effective initiator for the ring-opening polymerization of ε-caprolactone: the non-isothermal kinetics, mechanism, and initiator’s performance in polymer synthesis

Dibutyltin(IV) maleate as a new effective initiator for the ring-opening polymerization of ε-caprolactone: the non-isothermal kinetics, mechanism, and initiator’s performance in polymer synthesis

Migration study of organotin compounds from food packaging by surface-enhanced Raman scattering

The potential of surface-enhanced Raman scattering (SERS) has been investigated for the rapid analysis of two representative organotin compounds (OTCs): dibutyltin maleate (DTM) and tributyltin chloride (TBT), after migration tests from polyvinyl chloride (PVC), as a model food packaging material in aqueous food simulant (acetic acid 3% w/v). OTCs, often used as heat stabilizers additives for PVC, are classified as endocrine disrupting chemicals (EDCs) and their migration potential has to be controlled in compliance with the normative prescriptions for food contact materials. In this study, colloidal silver nanoparticles (AgNPs) were applied as liquid SERS substrate for direct-in-liquid analysis of food simulant after standardized migration tests of PVC samples spiked with OTCs. Promising results were obtained, reaching detection limits below the permitted limits for the considered OTCs (i.e. 0.15 mg/l): DTM and TBT were detected down to 0.01 mg/l and 0.08 mg/l, respectively. Calibration curves were calculated for standard solutions of DTM and TBT in the dynamic range between 0 and 1 mg/l (reduced χ2 = 0.8), and 0.5–5 mg/l (reduced χ2 = 0.2), respectively. Migrated TBT and DTM were detected in the food simulant, specifically identified and quantified by SERS, with a measurement uncertainty around 10% in all cases. In particular, it was found that TBT can migrate in higher amount compared to DTM when the PVC film is in contact with a slightly acidic matrix. These results were further confirmed by inductively coupled plasma-mass spectrometry and UV–Vis spectroscopy. In the present study, direct-in-liquid SERS approach showed to be very promising because it provides a fast response and it allows to overcome most of the common drawbacks of solid SERS substrates due to inhomogeneity problems and low repeatability.

The research of dibutyltin polymer on the thermal stability of PVC

A novel series of polymeric thermal stabilizers were synthesized by radical solution polymerization using dibutyltin maleate (DBTM), styrene (St) as main comonomers, methyl acrylate (MA), N-phenylmaleimide (NPMI), N-p-chlorophenylmaleimide (NCPMI), N-(4-nitrophenyl)maleimide (NNOPMI) as modified monomers, respectively, and AIBN as the initiator, namely P(DBTM/St), P(DBTM/St/MA), P(DBTM/St/NPMI), P(DBTM/St/NCPMI), and P(DBTM/St/NNOPMI). The structures were characterized by FTIR and 1H NMR spectra. The molecular weight and its distribution were measured with GPC. The dynamic stability was studied by the measure of hydrogen chloride from PVC, which were added into quantitive thermal stabilizers before processing. The depressant effects of thermal stabilizers were researched on discoloration due to degradation with thermal aging method. The parameters of thermal degradation dynamics were calculated by the Kissinger method. The effect order of the five stabilizers on thermal stability was P(DBTM/St/MA) > P(DBTM/St) > P(DBTM/St/NPMI) > P(DBTM/St/NCPMI)> (DBTM/St/NNOPMI).

Evaluation of the Thermal Stabilization Effect of Maleic Anhydride Derivatives on Polyvinyl Chloride

Here, we synthesized a series of polymeric thermal stabilizers for polyvinyl chloride (PVC) based on maleic anhydride derivatives, including N-phenylmaleimide (NPMI), N-p-chlorophenyl maleimide (NCIPMI), N-p-nitrophenyl maleimide (NNOPMI), dibutyltin maleate (DBTM) and dioctyltin maleate (DOTM). Five specimens were prepared by mixing and rolling through a blending machine and a double-roller mixer, respectively. These samples were first subjected to thermal degradation in a 180°C hot oven, and fractions were collected every 10 min, followed by spotting on a slip of test paper. From the degree of color change in the test paper, the influences of these compounds on the thermal stability of PVC were estimated and such mechanisms were also discussed.

Synthesis and Characterization of Organotin Containing Copolymers: Reactivity Ratio Studies

Organotin monomers containing dibutyltin groups – dibutyltin citraconate (DBTC) as a new monomer and dibutyltin maleate (DBTM) – were synthesized. Free radical copolymerizations of the organotin monomers with styrene (ST) and butyl acrylate (BA) were performed. The overall conversion was kept low (≤15% wt/wt) for all studied samples and the copolymers composition was determined from tin analysis using the Gillman and Rosenberg method. The reactivity ratios were calculated from the copolymer composition using the Fineman-Ross (FR) method. The synthesized monomers were characterized by elemental analysis, 1H-, 13C-NMR and FTIR spectroscopy.

Electrical properties and the thermal and photochemical stability of poly(vinyl chloride) films stabilized with some maleyl amide polymers

AbstractSome maleyl amide polymers were prepared and evaluated as thermal and photochemical stabilizers for rigid poly(vinyl chloride) (PVC). Thermal degradation was determined by measuring the rate of dehydrochlorination potentiometrically. Also, the degree of discoloration was measured for both the thermally degraded and the photochemically degraded PVC. Dibutyltin maleate heat stabilizer was used for comparison in thermal and photodegradation. The applied polymers showed stabilizing efficiency in both thermal and photodegradation by decreasing the rate of degradation, degree of discoloration, and percentage weight loss. The amide polymer of melamine gave better stabilizing efficiency than those of p‐phenylenediamine and m‐phenylenediamine. A dielectric study was carried out over a frequency range from 100 Hz to 100 kHz at room temperature (∼22°C). The results revealed that the stabilizing effect of these maleyl amide polymers depends on the type of stabilizer and its concentration. The dielectric data for the investigated systems were found to be fitted by two absorption regions using the Fröhlich function. These regions are ascribed to the Maxwell–Wagner effect and to intramolecular motion involving the rotation of various segments of the side group as the main chain motion is restricted. The study led to a conclusion that the greater stabilizing efficiency of the melamine amide polymer may be due to the presence of a free amino group (NH2) that can participate in the stabilization process. J. VINYL ADDIT. TECHNOL., 13:206–214, 2007. © 2007 Society of Plastics Engineers

Organic thermal stabilizers for rigid poly(vinyl chloride) VII. Effect of mixing 2-benzimidazolyl- ω-phenylpropenylidineacetonitrile with some commercial stabilizers

The effect of mixing 2-benzimidazolyl- ω-phenylpropenylidineacetonitrile (BPAN) with each of the reference stabilizers: dibasic lead carbonate (DBLC), dibasic lead stearate (DBLS), barium–cadmium–zinc stearate (Ba–Cd–Zn stearate), or dibutyltin maleate (DBTM) on the stabilizing efficiency in thermal degradation of rigid PVC at 180 °C, in air, has been investigated. Mixing was effected in the range of 0–100 wt.% of BPAN relative to each of the reference stabilizers. The stabilizing efficiency was evaluated by measuring the length of the induction period ( T s), the period during which no detectable amounts of hydrogen chloride gas could be observed, and also from the rate of dehydrochlorination as measured by continuous potentiometric determination on the one hand, and the extent of discoloration of the degraded polymer samples on the other. The results show a true synergistic effect from the combination of BPAN with any of the reference stabilizers. Mixing of the stabilizers improves the T s values, decreases the rate of dehydrochlorination, and lowers the extent of discoloration of the polymer. The synergism reaches its maximum when the BPAN is mixed with either DBLS or Ba–Cd–Zn stearate in weight ratio of 25/75%, respectively. In case of DBLC or DBTM, the maximum synergism was attained when the stabilizers mixtures were in equivalent weight ratio (50/50%). The observed synergism may be attributed to the different mechanisms by which the investigated and the reference stabilizers work.

Organic thermal stabilizers for rigid poly(vinyl chloride) VI. Effect of mixing p-chloro- N-phenylphthalimide with some commercial stabilizers

The effect of mixing p-chloro- N-phenylphthalimide ( p-Cl- NØPI) with the reference stabilizers: dibasic lead carbonate (DBLC), dibasic lead stearate (DBLS), barium–cadmium–zinc stearate (Ba–Cd–Zn stearate), n-octyltin mercaptide ( n-OTM) or dibutyltin maleate (DBTM) on the stabilizing efficiency in thermally degradation of rigid PVC at 180 °C, in air, has been investigated. Mixing was effected in the range of 0–100 wt.% of p-Cl- NØPI relative to the reference stabilizers. The stabilizing efficiency is evaluated by measuring the length of the induction period ( T s), the period during which no detectable amounts of hydrogen chloride gas could be observed, and also from the rate of dehydrochlorination as measured by continuous potentiometric determination on one hand, and the extent of discoloration of the degraded polymer samples on the other. The results reveal that mixing of the stabilizers improves the Ts values, decreases the rate of dehydrochlorination and lowers the extent of discoloration of the polymer. This improvement attains its maximum when the p-Cl- NØPI is mixed with any of DBLC, DBLS, Ba–Cd–Zn stearate or DBTM reference stabilizers in weight ratio of 25/75%, respectively. Mixing of p-Cl- NØPI with n-OTM is an exception, as maximum synergism was attained at equivalent weight ratio (50/50%).

Organic thermal stabilizers for rigid poly(vinyl chloride).Part X: N-acryloyl- N′- p-substituted phenylthiourea derivatives

N-Acryloyl- N′- p-substituted phenylthiourea derivatives have been examined as thermal stabilizers or co-stabilizers for rigid poly(vinyl chloride) in air, at 180 °C. Their high stabilizing efficiency is proved by their higher induction period if compared with dibasic lead carbonate, barium–cadmium–zinc stearate and dibutyl tin maleate reference stabilizers used industrially, but with higher dehydrochlorination rate and higher extent of discoloration. Mixing these derivatives with reference stabilizers in different proportions greatly improves both the induction period and the degradation rate. A probable ionic mechanism for the stabilizing action of N-Acryloyl- N′- p-substituted phenylthiourea derivatives has been proposed. The stabilizing efficiency is attributed to the replacement of the labile chloride ions on the PVC chains by a relatively more stable moiety of the organic stabilizer.

Study of Microwave Irradiation Polymerization in the Presence of Different Carriers

ABSTRACT The influence of the presence of an inorganic carrier in the polymerization systems was investigated in this paper. Ten polymerization systems that contained different inorganic carriers such as Al2O3, SiO2 were studied. The ten polymerization systems are dibutyltin Maleate (DBTM) and allyl thiourea (AT), DBTM and stearic acid vinyl ester (SAVE), SAVE and maleic anhydride (MH), SAVE and acrylamide (AM), itaconic acid (IA) and AM, SAVE and IA, AM and MH, IA, sodium acrylate (AANa), AM. It was found that the activity of monomer can be changed in the presence of a carrier and furthermore, the different species of carrier influence the activity of same monomer differently in the polymerization.

Organic thermal stabilizers for rigid poly(vinyl chloride) V. Benzimidazolylacetonitrile and some of its derivatives

2-Benzimidazolylacetonitrile (BAN) and some of its conjugated unsaturated derivatives namely: 2-benzimidazolylbenzylidineacetonitrile (BBeAN), 2-benzimidazolyl-ω-phenylpropenylidineacetonitrile (BPAN) and 2-benzimidazolylbut-2-enylidineacetonitrile (BBuAN) have been investigated as organic thermal stabilizers for rigid PVC at 180 °C in air. Their stabilizing efficiencies are based on measuring the length of the induction period ( T s), the period during which no detectable amounts of HCl gas could be observed, and also from the rate of dehydrochlorination as measured by the continuous potentiometric titration on the one hand, and the extent of discoloration of the degraded polymer samples on the other. The stabilizing efficiencies of the investigated stabilizers were compared with that of dibasic lead carbonate (DBLC), dibasic lead stearate (DBLS), barium–cadmium–zinc stearate (Ba–Cd–Zn stearate) and dibutyltin maleate (DBTM) which are commonly used industrial stabilizers. The results reveal the higher stabilizing efficiency of the investigated materials relative to the reference stabilizers concerning the T s values. However, the rate of dehydrochlorination at the later stages of degradation for PVC stabilized with the investigated stabilizers is found to be relatively higher than that in the presence of reference stabilizers. These experimental findings indicate that almost all the stabilizers actions are exhausted during the induction period. The stabilizing efficiencies of the investigated stabilizers can be attributed to the replacement of the labile chlorine atoms on the polymer chains by a relatively more thermally stable groups derived from the stabilizer. This substitution reaction proceeds most probably through a radical mechanism. Moreover, the results also reveal the effect of the extent of conjugated unsaturates in the organic stabilizer molecule. The stabilizing potency of the investigated materials increases with the extent of their conjugated unsaturation sites. On the other hand, the results also reveal that while the extent of discoloration of thermally degraded PVC in the presence of BPAN stabilizer is comparable with most of the investigated reference stabilizers, the other derivatives showed a relatively higher extent of discoloration.

Microwave radiation copolymerization of dibutyltin maleate and allyl thiourea

Microwave radiation copolymerization of dibutyltin maleate and allyl thiourea

Organic thermal stabilizers for rigid poly(vinyl chloride) III. Crotonal and cinnamal thiobarbituric acids

Crotonal thiobarbituric acid (CTBA) and cinnamal thiobarbituric acid (CiTBA) have been investigated as thermal stabilizers for rigid poly (vinyl chloride) (PVC) at 180°C in air. Their stabilizing efficiency is evaluated by measuring the length of the induction period ( T s), the period during which no detectable amounts of hydrogen chloride gas could be observed, and also from the rate of dehydrochlorination as measured by continuous potentiometric titration on one hand and the extent of discoloration of the degraded polymer on the other. The results reveal the higher stabilizing efficiency of the investigated materials as compared with industrially used thermal stabilizers such as dibasic lead carbonate (DBLC), dibasic lead stearate (DBLS), n-octyl tin mercaptide ( n-OTM), dibutyl tin maleate (DBTM) and barium–cadmium–zinc stearate (Ba–Cd–Zn stearate). This is well illustrated by the longer T s values, and by the lower rates both of dehydrochlorination and discoloration of the polymer during degradation relative to those of the reference stabilizers. A radical mechanism for the stabilizing effect of the investigated materials is suggested. The results indicate the important role played by the extent of conjugation in thiobarbituric acid derivatives on the stabilizing efficiency of the stabilizers. The stabilizing potency of the stabilizer increases with the extent of conjugation. The effect of blending CiTBA with either of the reference stabilizers on the stabilizing efficiency of the thermally degraded rigid PVC has been also investigated. The results reveal that mixing of the stabilizers improve both the T s values, the rate of dehydrochlorination and the extent of discoloration. This improvement attains its maximum when both the investigated and the reference stabilizers are taken in equivalent weight ratios.

Organic thermal stabilizers for rigid poly(vinyl chloride) I. Barbituric and thiobarbituric acids

Barbituric acid (BA) and thiobarbituric acid (TBA) have been investigated as thermal stabilizers for rigid poly(vinyl chloride) (PVC) at 180°C, in air. The efficiency of these compounds as thermal stabilizers was evaluated by measuring the length of the induction period ( T s), during which no detectable amount of hydrogen chloride gas could be observed, and also from the rate of dehydrochlorination as measured by continuous potentiometric titration on one hand, and the extent of discoloration of the degraded polymer on the other. The stabilizing efficiencies were compared with that of dibasic lead carbonate (DBLC), dibasic lead stearate (DBLS), barium–cadmium–zinc stearate (Ba–Cd–Zn stearate), n-octyl tin mercaptide ( n-OTM) and dibutyl tin maleate (DBTM). With the exception of DBTM reference stabilizer which shows a comparable stabilizing efficiency with BA and TBA, the investigated organic stabilizers exhibit a greater efficiency than those of all other reference stabilizers. Moreover, they impart better color stability to the degraded samples. A radical mechanism for the stabilizing action is suggested. The stabilizing efficiency is attributed to the replacement of the labile chlorine atoms on the PVC chains by a relatively more stable moiety of the stabilizer. This disrupts the formation of conjugated double bonds, which are responsible for the discoloration.

Microwave radiation copolymerization of dibutyltin maleate and allyl thiourea

This article reports on an investigation of microwave radiation copolymerization of dibutyltin maleate (DBTM) with allyl thiourea (AT) and the copolymers it produced. The effect of radiation energy, composition of monomer, amount of initiator, and amount and kind of inorganic oxide (Al2O3 or SiO2) as reaction sensitizers on the copolymerization conversion and polymer-inherent viscosity were systematically studied, and simultaneously compared with the relevant conventional thermopolymerization. The reactivity ratios for DBTM and AT were determined using liquid chromatography. The copolymerization mechanism of microwave radiation was probed using a free-radical capturing agent (DPPH). The copolymers obtained were used as heat-stabilization agent of PVC resin. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 312–318, 2001

1-Cyanoethanoyl-4-acryloyl thiosemicarbazide and its metal complexes as thermal stabilizers for rigid poly(vinyl chloride)

1-Cyanoethanoyl-4-acryloyl thiosemicarbazide (CEATS) and its metal complexes with Sn 2+, Cd 2+, Co 2+ ions have been investigated as thermal stabilizers for rigid poly(vinyl chloride). The results reveal that the stabilizing efficiency of CEATS is comparable to that of the commonly used industrial stabilizers, while the stabilizing efficiencies of CEATS complexes greatly exceed that of the parent molecule. CEATS as a co-stabilizer with reference stabilizers namely Cd–Ba stearates, dibutyl tin maleate, or basic lead sulfate led to a synergistic effect. A probable mechanism expressing the interaction of CEATS molecule with metal salts stabilizers has been proposed.

The thermooxidative degradation of poly(vinylchloride): 3. The stabilising action of dibutyltin maleate and trisnitro (1,3-dihydroxy-2-hydroxymethyl-2-nitropropane). Effect of outdoor exposure on PVC

The effects of the stabilising action of admixed mixtures of dibutyltin maleate and trisnitro and its ester homologues on polyvinyl chloride exposed to natural atmosphere were studied. The degradation and stabilisation reactions were monitored by i.r., colour formation, tensile strength, elongation at break, reduced viscosity as well as determination of time to embrittlement. Observed reductions in carbonyl group formation, lack of colour formation and generally improved mechanical properties of the stabilised PVC sample indicated effective reduction in degradation reactions. The stabilising agents containing 7.2×10 −3 mol% DBTM in admixture with 10×10 −4 mol% of stearyl ester of trisnitro was most effective.

The photooxidative degradation of poly(vinylchloride)—2. The stabilising action of dibutyltin maleate and trisnitro (1,3-dihydroxyl-2-hydroxymethyl-2-nitropropane) on PVC from ultraviolet light radiation

The photooxidative degradation and stabilisation of poly(vinylchloride) (PVC) have been studied using dibutyltin maleate (DBTM) alone and mixed with varying amounts of trisnitro (1,3-dihydroxyl-2-hydroxylmethyl-2-nitropropane) compounds as stabilisers. Films of the unstabilised and stabilised PVC were exposed to ultraviolet (UV) light ageing at room temperature. The degradation reactions were monitored by IR, colour formation, tensile strength and elongation at break, as well as determination of time to embrittlement. The stabilising action of 7.2 × 10 −3 mol% DBTM mixed with 10 × 10 −4 mol% of the lauryl ester of the trisnitro compounds proved most effective in limiting photooxidative reactions in PVC.

Speciation of organotin compounds released from poly(vinyl chloride) at increased temperature by gas chromatography with atomic emission detection

A method for sampling and analysis of airborne organotin compounds emitted from poly(vinyl chloride) (PVC) was developed and tested. The organotins originating from dibutyltin maleate, mono- and dioctyltin mercaptoacetate stabilizers were released from PVC under controlled conditions and recovered from the sorption part of a sampling tube. The composition of the sampling material in the tube was optimized to get a reproducible release and complete sorption of the target compounds and to simplify the extraction procedure. An optimized extraction procedure together with aqueous phase derivatization and determination by gas chromatography–atomic emission detection resulted in a selective and reproducible determination of the organotin compounds. Influences of different thermoplast temperatures, heating times, purge flow gases and purge flow rates on the release of organotins from PVC have been evaluated. Significant amounts of dibutyltin were found to be released from a PVC sample stabilized with dibutyltin maleate at temperatures of 108°C to 200°C.

The thermooxidative degradation of poly(vinyl chloride). Part I. The stabilising action of dibutyltin maleate and trisnitro (1,3-dihydroxyl-2-hydroxymethyl-2-nitropropane) on PVC in air

The thermooxidative degradation and stabilisation of poly(vinyl chloride) (PVC) have been studied using dibutyltin maleate (DBTM) alone and in admixture with varying amounts of trisnitro (1,3-dihydroxy-2-hydroxymethyl-2-nitropropane) compounds as stabilisers. Films of the unstabilised and stabilised PVC were exposed to oven ageing at 100 °C. The degradation reactions were monitored by infrared spectroscopy, colour and gel formation, and determination of time to embrittlement. The results indicate that the stabilising agents containing 7.2 × 10 −3 mol% DBTM in admixture with 5 × 10 −4 mol% of the stearyl ester of the trisnitro compounds are most effective. The relevant mechanisms of stabilisation are discussed.