Adrian Boborodea | UCLouvain (University of Louvain) (original) (raw)

Papers by Adrian Boborodea

Research paper thumbnail of Characterization of Low-Density Polyethylene in Dibutoxymethane by High-Temperature Gel Permeation Chromatography with Triple Detection

Research paper thumbnail of Characterization of Polyethylene in Dibutoxymethane by High Temperature Gel Permeation Chromatography with Triple Detection

International Journal of Polymer Analysis and Characterization, Mar 11, 2015

ABSTRACT The study presents the possibility to replace the 1,2,4-trichlorobenzene (TCB) recommend... more ABSTRACT The study presents the possibility to replace the 1,2,4-trichlorobenzene (TCB) recommended by ASTM D 6474 for the analysis by gel permeation chromatography (GPC) of linear polyethylenes with dibutoxymethane (DBM, butylal), a halogen free and less toxic solvent. The molecular weight distributions as well as the K and alpha parameters of the Mark-Houwink-Sakurada relationship were measured for polyethylene solutions in TCB, and DBM, using a GPC system with triple detection (light scattering, differential refractive index and viscometer). For commercial metallocene polyethylene resins typically used for film and packaging applications, the GPC method in DBM provided comparable results to those obtained in TCB.

Research paper thumbnail of Fast Analytical Temperature Rising Elution Fractionation (ATREF) Method

International Journal of Polymer Analysis and Characterization, Feb 28, 2014

ABSTRACT Analytical temperature rising elution fractionation (TREF) is a complementary technique ... more ABSTRACT Analytical temperature rising elution fractionation (TREF) is a complementary technique of gel permeation chromatography (GPC) for the analysis of polyolefin structure. By connecting a high-temperature GPC with a gas chromatograph (GC) oven it is possible to build a fast analytical TREF, which permits a dramatic reduction in analysis time by directly injecting the polymer solution onto the cold column, as compared with the traditional TREF in which the slow cooling step usually takes more than 40 h. The method was successfully applied on six commercial random and homo polypropylenes for which similar thermograms were obtained for fast- and slow-cooling TREF. The obtained results show subtle differences in the behavior of polypropylene melting in solution as compared with previously analyzed polyethylene. The most important is the difference of 12.6°C between the melting temperatures in the presence of trichlorobenzene and xylene, which is much higher for polypropylene than the 3.7°C measured for polyethylene.

Research paper thumbnail of An Improved Analytical Temperature-Rising Elution Fractionation System for Automated Analysis of Polyethylenes

temperature-rising elution fractionation overcomes the limitations of preparative temperature-ris... more temperature-rising elution fractionation overcomes the limitations of preparative temperature-rising elution fractionation by reducing the column and sample sizes considerably and by continuously monitoring the amount of the eluted polymer fractions as a function of column temperature using an on-line detector.

Research paper thumbnail of Polymerization of vinyl acetate in microemulsion with methanol

Research paper thumbnail of Evaluating the Temperature Shift in Analytical Temperature Rising Elution Fractionation

Lc Gc North America

This article presents a new method to evaluate the temperature shift observed in analytical tempe... more This article presents a new method to evaluate the temperature shift observed in analytical temperature rising elution fractionation (ATREF). The evaluation is based on the dependence of the measured peak temperature as a function of heating rates. Application of the proposed method does not require any knowledge of the fluid circuit characteristics geometry and avoids the use of narrow preparative TREF standards. The results are found to be more accurate than the method that is usually applied. http://www.chromatographyonline.com/lcgc/Article/Evaluating-the-Temperature-Shift-in-Analytical-Tem/ArticleStandard/Article/detail/814082

Research paper thumbnail of Assessing the Suitability of a Green Solvent for GPC and TREF Analyses of Polyethylene

Lc Gc North America

The study presents results of gel permeation chromatography (GPC) and analytical temperature risi... more The study presents results of gel permeation chromatography (GPC) and analytical temperature rising elution fractionation (TREF) of polyethylene in butylal (dibutoxymethane, a halogen-free solvent). A comparison is made with the results obtained using 1,2,4-trichlorobenzene showing that changing the solvent to butylal does not require any modification of the existing GPC instruments and has additional advantages such as lower toxicity, increased detector signal for polystyrene standards, and broadening domain of crystallization temperatures for TREF. http://www.chromatographyonline.com/node/246101

Research paper thumbnail of Assessing the Suitability of a Green Solvent for GPC and TREE Analyses of Polyethylene

LC GC Europe

This study presents results of gel permeation chromatography (GPC) and analytical temperature ris... more This study presents results of gel permeation chromatography (GPC) and analytical temperature rising elution fractionation (TREF) of polyethylene in butylal (dibutoxymethane, a halogen-free solvent). A comparison is made with the results obtained using 1,2,4-trichlorobenzene showing that changing the solvent to butylal does not require any modification of the existing GPC instruments and has additional advantages such as lower toxicity, increased detector signal for polystyrene standards, and broadening domain of crystallization temperatures for TREF.

Research paper thumbnail of Characterization of Polypropylene in Dibutoxymethane by High Temperature Gel Permeation Chromatography with Triple Detection

International Journal of Polymer Analysis and Characterization, 2015

Research paper thumbnail of Characterization of Polyethylene in Dibutoxymethane by High-Temperature Gel Permeation Chromatography with Triple Detection

International Journal of Polymer Analysis and Characterization, 2015

ABSTRACT The study presents the possibility to replace the 1,2,4-trichlorobenzene (TCB) recommend... more ABSTRACT The study presents the possibility to replace the 1,2,4-trichlorobenzene (TCB) recommended by ASTM D 6474 for the analysis by gel permeation chromatography (GPC) of linear polyethylenes with dibutoxymethane (DBM, butylal), a halogen free and less toxic solvent. The molecular weight distributions as well as the K and alpha parameters of the Mark-Houwink-Sakurada relationship were measured for polyethylene solutions in TCB, and DBM, using a GPC system with triple detection (light scattering, differential refractive index and viscometer). For commercial metallocene polyethylene resins typically used for film and packaging applications, the GPC method in DBM provided comparable results to those obtained in TCB.

Research paper thumbnail of Characterization of Polyethylene Using Fast Analytical Temperature Rising Elution Fractionation with Triple Detection (ATREF 3D)

International Journal of Polymer Analysis and Characterization, 2015

ABSTRACT A commercially available gel permeation chromatograph with triple detection (GPC3D) was ... more ABSTRACT A commercially available gel permeation chromatograph with triple detection (GPC3D) was coupled with a gas chromatograph to obtain a fast analytical temperature rising fractionation system with triple detection (ATREF3D). On this hybrid instrument we developed a fast method for evaluating in one run, and with less than 0.5 mg of sample, the density, molecular weight, and the type of polyethylene. The method was evaluated with excellent results on commercial polyethylene resins typically used for film and packaging applications.

Research paper thumbnail of Characterization of Polyphenylene Sulfide Using Gel Permeation Chromatography with Triple Detection

International Journal of Polymer Analysis and Characterization, 2015

ABSTRACT The increasing world demand for polyphenylene sulfide (PPS) due to its unique properties... more ABSTRACT The increasing world demand for polyphenylene sulfide (PPS) due to its unique properties has augmented the pressure on development of analytical methods to evaluate its molecular weight distribution and structure. Whilst gel permeation with triple detection (GPC3D) has been considered for PPS analysis, its development and effectiveness has been impaired because of, firstly, the high temperature needed to maintain solubility (>205°C), and, secondly, a very low dn/dc for the polystyrene calibration standards in 1-chloronaphthalene. This article presents practical recommendations to overcome these early difficulties by discussing the results obtained on PPS samples analyzed with a commercially available GPC3D instrument. http://www.tandfonline.com/doi/full/10.1080/1023666X.2015.988902#abstract

Research paper thumbnail of Updated “Onion Skin” Model for Temperature Rising Elution Fractionation

International Journal of Polymer Analysis and Characterization, 2015

ABSTRACT Recent developments on temperature rising elution fractionation (TREF) technique, unders... more ABSTRACT Recent developments on temperature rising elution fractionation (TREF) technique, understanding the impact strength of polyethylene blends based on their chemical structure, as well as ongoing discussions on REACH legislation regarding the oligomer fraction of polymers, are all reasons for better comprehension of the separation mechanism in TREF. To achieve this goal, two carefully chosen blends of linear metallocene polyethylene were analyzed by TREF over a large domain of crystallization rates. The results allowed updating the “onion skin” model for the crystallization kinetics during the cooling step of TREF. The advantages and limitations of TREF technique for different applications are discussed.

Research paper thumbnail of Correlation Between GPC, DSC and Analytical TREF for Linear Polyethylene

International Journal of Polymer Analysis and Characterization, 2015

ABSTRACT The analytical temperature rising elution fractionation (TREF) of linear polyethylene (P... more ABSTRACT The analytical temperature rising elution fractionation (TREF) of linear polyethylene (PE) samples with different densities was done in 1-chloronaphthalene using a gel permeation chromatograph (GPC) coupled with a gas chromatograph (GC). The corrected peak elution temperatures completed the previous data in trichlorobenzene, xylene and dibutoxymethane. A mathematical correlation was found for diluted linear PE samples, between the α parameter of the Mark-Houwink-Sakurada (MHS) equation governing the retention time in GPC, the bulk melting temperature measured by differential scanning calorimetry (DSC) and the TREF peak elution temperature. The extrapolation to the melting temperature measured by DSC gives α = 0.5, thus confirming the hypothesis that polymer conformations in the melt are similar with those in a theta solvent.

Research paper thumbnail of Elution Temperatures of Polyethylene Copolymers in Temperature Rising Elution Fractionation (TREF): Comparison in Xylene and Trichlorobenzene Diluents

International Journal of Polymer Analysis and Characterization, 2014

ABSTRACT Temperature rising elution fractionation (TREF) became the preferred technique to charac... more ABSTRACT Temperature rising elution fractionation (TREF) became the preferred technique to characterize the short chain branching distribution of polyethylene copolymers. Due to technical limitations, preparative TREF (PTREF) is usually done in xylene, while trichlorobenzene is used in analytical TREF (ATREF). Attempts to correlate the TREF elution temperatures based on data published by different authors erroneously showed higher elution temperatures for xylene than for trichlorobenzene. Our study rectifies this error. The experiments were done in both solvents on the same analytical TREF instrument. For the analyzed polyethylene copolymers, we found that the average elution temperature in xylene is 3.7° ± 1°C lower than in trichlorobenzene.

Research paper thumbnail of Fast Analytical Temperature Rising Elution Fractionation (TREF) of Polypropylenes

International Journal of Polymer Analysis and Characterization, 2015

ABSTRACT Analytical temperature rising elution fractionation (TREF) is a complementary technique ... more ABSTRACT Analytical temperature rising elution fractionation (TREF) is a complementary technique of gel permeation chromatography (GPC) for the analysis of polyolefin structure. By connecting a high-temperature GPC with a gas chromatograph (GC) oven it is possible to build a fast analytical TREF, which permits a dramatic reduction in analysis time by directly injecting the polymer solution onto the cold column, as compared with the traditional TREF in which the slow cooling step usually takes more than 40 h. The method was successfully applied on six commercial random and homo polypropylenes for which similar thermograms were obtained for fast- and slow-cooling TREF. The obtained results show subtle differences in the behavior of polypropylene melting in solution as compared with previously analyzed polyethylene. The most important is the difference of 12.6°C between the melting temperatures in the presence of trichlorobenzene and xylene, which is much higher for polypropylene than the 3.7°C measured for polyethylene.

Research paper thumbnail of Progress on Fast Analytical Temperature Rising Elution Fractionation (ATREF) Technique for Practical Applications

International Journal of Polymer Analysis and Characterization, 2014

ABSTRACT Fast analytical temperature rising elution fractionation (ATREF) is a recently proposed ... more ABSTRACT Fast analytical temperature rising elution fractionation (ATREF) is a recently proposed method to evaluate the molecular structure of polyolefins with unimodal distributions. In this article, we compare the results obtained by this method and the classical slow cooling rate ATREF. An interpretation of previous results found in the literature is proposed in order to explain one of the limitations usually associated with this technique. Practical recommendations are given to build columns adapted to this technique and to efficiently adjust the method parameters.

Research paper thumbnail of Elaboration of poly(lactic acid)/halloysite nanocomposites by means of water assisted extrusion: structure, mechanical properties and fire performance

RSC Adv., 2014

Poly(lactic acid) (PLA)/Halloysite nanotubes (HNTs) nanocomposites were prepared using a water as... more Poly(lactic acid) (PLA)/Halloysite nanotubes (HNTs) nanocomposites were prepared using a water assisted extrusion process. Morphology, structure, thermomechanical properties and fire performance of these nanocomposites were compared to those obtained in the case of nanocomposites elaborated via conventional extrusion process. Whatever the elaboration route used, mechanical tests indicate that HNTs have a reinforcing effect ascribed to the dispersion, at least partial, of the HNTs into the PLA matrix. Differential Scanning Calorimetry also shows that HNTs infers on the PLA crystallization and play the role of nucleating agent.

Research paper thumbnail of Anionic and ionic coordinative polymerization ofL-lactide

Polymers for Advanced Technologies, 1998

The potassium naphthalenide complex with 18-crown-6 is able to initiate anionic polymerization of... more The potassium naphthalenide complex with 18-crown-6 is able to initiate anionic polymerization of L-lactide at 20°C. This type of anionic initiator does not have to be removed from the polymer as it does not affect metabolic processes. The ionic polymerization of L-lactide with an ...

Research paper thumbnail of Copolymerization of the pair maleic anhydride-dicyclopentadiene: I. Copolymerization and post-copolymerization at high conversion

Polymer International, 2005

Dicyclopentadiene (DCPD) is one of the most accessible cyclo-olefins. Indeed, cyclopentadiene is ... more Dicyclopentadiene (DCPD) is one of the most accessible cyclo-olefins. Indeed, cyclopentadiene is present at concentrations of up to 20 % in commonly recovered fractions following pyrolysis of the crude oil C5. Its stable form (below 100 °C) is represented by the corresponding ...

Research paper thumbnail of Characterization of Low-Density Polyethylene in Dibutoxymethane by High-Temperature Gel Permeation Chromatography with Triple Detection

Research paper thumbnail of Characterization of Polyethylene in Dibutoxymethane by High Temperature Gel Permeation Chromatography with Triple Detection

International Journal of Polymer Analysis and Characterization, Mar 11, 2015

ABSTRACT The study presents the possibility to replace the 1,2,4-trichlorobenzene (TCB) recommend... more ABSTRACT The study presents the possibility to replace the 1,2,4-trichlorobenzene (TCB) recommended by ASTM D 6474 for the analysis by gel permeation chromatography (GPC) of linear polyethylenes with dibutoxymethane (DBM, butylal), a halogen free and less toxic solvent. The molecular weight distributions as well as the K and alpha parameters of the Mark-Houwink-Sakurada relationship were measured for polyethylene solutions in TCB, and DBM, using a GPC system with triple detection (light scattering, differential refractive index and viscometer). For commercial metallocene polyethylene resins typically used for film and packaging applications, the GPC method in DBM provided comparable results to those obtained in TCB.

Research paper thumbnail of Fast Analytical Temperature Rising Elution Fractionation (ATREF) Method

International Journal of Polymer Analysis and Characterization, Feb 28, 2014

ABSTRACT Analytical temperature rising elution fractionation (TREF) is a complementary technique ... more ABSTRACT Analytical temperature rising elution fractionation (TREF) is a complementary technique of gel permeation chromatography (GPC) for the analysis of polyolefin structure. By connecting a high-temperature GPC with a gas chromatograph (GC) oven it is possible to build a fast analytical TREF, which permits a dramatic reduction in analysis time by directly injecting the polymer solution onto the cold column, as compared with the traditional TREF in which the slow cooling step usually takes more than 40 h. The method was successfully applied on six commercial random and homo polypropylenes for which similar thermograms were obtained for fast- and slow-cooling TREF. The obtained results show subtle differences in the behavior of polypropylene melting in solution as compared with previously analyzed polyethylene. The most important is the difference of 12.6°C between the melting temperatures in the presence of trichlorobenzene and xylene, which is much higher for polypropylene than the 3.7°C measured for polyethylene.

Research paper thumbnail of An Improved Analytical Temperature-Rising Elution Fractionation System for Automated Analysis of Polyethylenes

temperature-rising elution fractionation overcomes the limitations of preparative temperature-ris... more temperature-rising elution fractionation overcomes the limitations of preparative temperature-rising elution fractionation by reducing the column and sample sizes considerably and by continuously monitoring the amount of the eluted polymer fractions as a function of column temperature using an on-line detector.

Research paper thumbnail of Polymerization of vinyl acetate in microemulsion with methanol

Research paper thumbnail of Evaluating the Temperature Shift in Analytical Temperature Rising Elution Fractionation

Lc Gc North America

This article presents a new method to evaluate the temperature shift observed in analytical tempe... more This article presents a new method to evaluate the temperature shift observed in analytical temperature rising elution fractionation (ATREF). The evaluation is based on the dependence of the measured peak temperature as a function of heating rates. Application of the proposed method does not require any knowledge of the fluid circuit characteristics geometry and avoids the use of narrow preparative TREF standards. The results are found to be more accurate than the method that is usually applied. http://www.chromatographyonline.com/lcgc/Article/Evaluating-the-Temperature-Shift-in-Analytical-Tem/ArticleStandard/Article/detail/814082

Research paper thumbnail of Assessing the Suitability of a Green Solvent for GPC and TREF Analyses of Polyethylene

Lc Gc North America

The study presents results of gel permeation chromatography (GPC) and analytical temperature risi... more The study presents results of gel permeation chromatography (GPC) and analytical temperature rising elution fractionation (TREF) of polyethylene in butylal (dibutoxymethane, a halogen-free solvent). A comparison is made with the results obtained using 1,2,4-trichlorobenzene showing that changing the solvent to butylal does not require any modification of the existing GPC instruments and has additional advantages such as lower toxicity, increased detector signal for polystyrene standards, and broadening domain of crystallization temperatures for TREF. http://www.chromatographyonline.com/node/246101

Research paper thumbnail of Assessing the Suitability of a Green Solvent for GPC and TREE Analyses of Polyethylene

LC GC Europe

This study presents results of gel permeation chromatography (GPC) and analytical temperature ris... more This study presents results of gel permeation chromatography (GPC) and analytical temperature rising elution fractionation (TREF) of polyethylene in butylal (dibutoxymethane, a halogen-free solvent). A comparison is made with the results obtained using 1,2,4-trichlorobenzene showing that changing the solvent to butylal does not require any modification of the existing GPC instruments and has additional advantages such as lower toxicity, increased detector signal for polystyrene standards, and broadening domain of crystallization temperatures for TREF.

Research paper thumbnail of Characterization of Polypropylene in Dibutoxymethane by High Temperature Gel Permeation Chromatography with Triple Detection

International Journal of Polymer Analysis and Characterization, 2015

Research paper thumbnail of Characterization of Polyethylene in Dibutoxymethane by High-Temperature Gel Permeation Chromatography with Triple Detection

International Journal of Polymer Analysis and Characterization, 2015

ABSTRACT The study presents the possibility to replace the 1,2,4-trichlorobenzene (TCB) recommend... more ABSTRACT The study presents the possibility to replace the 1,2,4-trichlorobenzene (TCB) recommended by ASTM D 6474 for the analysis by gel permeation chromatography (GPC) of linear polyethylenes with dibutoxymethane (DBM, butylal), a halogen free and less toxic solvent. The molecular weight distributions as well as the K and alpha parameters of the Mark-Houwink-Sakurada relationship were measured for polyethylene solutions in TCB, and DBM, using a GPC system with triple detection (light scattering, differential refractive index and viscometer). For commercial metallocene polyethylene resins typically used for film and packaging applications, the GPC method in DBM provided comparable results to those obtained in TCB.

Research paper thumbnail of Characterization of Polyethylene Using Fast Analytical Temperature Rising Elution Fractionation with Triple Detection (ATREF 3D)

International Journal of Polymer Analysis and Characterization, 2015

ABSTRACT A commercially available gel permeation chromatograph with triple detection (GPC3D) was ... more ABSTRACT A commercially available gel permeation chromatograph with triple detection (GPC3D) was coupled with a gas chromatograph to obtain a fast analytical temperature rising fractionation system with triple detection (ATREF3D). On this hybrid instrument we developed a fast method for evaluating in one run, and with less than 0.5 mg of sample, the density, molecular weight, and the type of polyethylene. The method was evaluated with excellent results on commercial polyethylene resins typically used for film and packaging applications.

Research paper thumbnail of Characterization of Polyphenylene Sulfide Using Gel Permeation Chromatography with Triple Detection

International Journal of Polymer Analysis and Characterization, 2015

ABSTRACT The increasing world demand for polyphenylene sulfide (PPS) due to its unique properties... more ABSTRACT The increasing world demand for polyphenylene sulfide (PPS) due to its unique properties has augmented the pressure on development of analytical methods to evaluate its molecular weight distribution and structure. Whilst gel permeation with triple detection (GPC3D) has been considered for PPS analysis, its development and effectiveness has been impaired because of, firstly, the high temperature needed to maintain solubility (>205°C), and, secondly, a very low dn/dc for the polystyrene calibration standards in 1-chloronaphthalene. This article presents practical recommendations to overcome these early difficulties by discussing the results obtained on PPS samples analyzed with a commercially available GPC3D instrument. http://www.tandfonline.com/doi/full/10.1080/1023666X.2015.988902#abstract

Research paper thumbnail of Updated “Onion Skin” Model for Temperature Rising Elution Fractionation

International Journal of Polymer Analysis and Characterization, 2015

ABSTRACT Recent developments on temperature rising elution fractionation (TREF) technique, unders... more ABSTRACT Recent developments on temperature rising elution fractionation (TREF) technique, understanding the impact strength of polyethylene blends based on their chemical structure, as well as ongoing discussions on REACH legislation regarding the oligomer fraction of polymers, are all reasons for better comprehension of the separation mechanism in TREF. To achieve this goal, two carefully chosen blends of linear metallocene polyethylene were analyzed by TREF over a large domain of crystallization rates. The results allowed updating the “onion skin” model for the crystallization kinetics during the cooling step of TREF. The advantages and limitations of TREF technique for different applications are discussed.

Research paper thumbnail of Correlation Between GPC, DSC and Analytical TREF for Linear Polyethylene

International Journal of Polymer Analysis and Characterization, 2015

ABSTRACT The analytical temperature rising elution fractionation (TREF) of linear polyethylene (P... more ABSTRACT The analytical temperature rising elution fractionation (TREF) of linear polyethylene (PE) samples with different densities was done in 1-chloronaphthalene using a gel permeation chromatograph (GPC) coupled with a gas chromatograph (GC). The corrected peak elution temperatures completed the previous data in trichlorobenzene, xylene and dibutoxymethane. A mathematical correlation was found for diluted linear PE samples, between the α parameter of the Mark-Houwink-Sakurada (MHS) equation governing the retention time in GPC, the bulk melting temperature measured by differential scanning calorimetry (DSC) and the TREF peak elution temperature. The extrapolation to the melting temperature measured by DSC gives α = 0.5, thus confirming the hypothesis that polymer conformations in the melt are similar with those in a theta solvent.

Research paper thumbnail of Elution Temperatures of Polyethylene Copolymers in Temperature Rising Elution Fractionation (TREF): Comparison in Xylene and Trichlorobenzene Diluents

International Journal of Polymer Analysis and Characterization, 2014

ABSTRACT Temperature rising elution fractionation (TREF) became the preferred technique to charac... more ABSTRACT Temperature rising elution fractionation (TREF) became the preferred technique to characterize the short chain branching distribution of polyethylene copolymers. Due to technical limitations, preparative TREF (PTREF) is usually done in xylene, while trichlorobenzene is used in analytical TREF (ATREF). Attempts to correlate the TREF elution temperatures based on data published by different authors erroneously showed higher elution temperatures for xylene than for trichlorobenzene. Our study rectifies this error. The experiments were done in both solvents on the same analytical TREF instrument. For the analyzed polyethylene copolymers, we found that the average elution temperature in xylene is 3.7° ± 1°C lower than in trichlorobenzene.

Research paper thumbnail of Fast Analytical Temperature Rising Elution Fractionation (TREF) of Polypropylenes

International Journal of Polymer Analysis and Characterization, 2015

ABSTRACT Analytical temperature rising elution fractionation (TREF) is a complementary technique ... more ABSTRACT Analytical temperature rising elution fractionation (TREF) is a complementary technique of gel permeation chromatography (GPC) for the analysis of polyolefin structure. By connecting a high-temperature GPC with a gas chromatograph (GC) oven it is possible to build a fast analytical TREF, which permits a dramatic reduction in analysis time by directly injecting the polymer solution onto the cold column, as compared with the traditional TREF in which the slow cooling step usually takes more than 40 h. The method was successfully applied on six commercial random and homo polypropylenes for which similar thermograms were obtained for fast- and slow-cooling TREF. The obtained results show subtle differences in the behavior of polypropylene melting in solution as compared with previously analyzed polyethylene. The most important is the difference of 12.6°C between the melting temperatures in the presence of trichlorobenzene and xylene, which is much higher for polypropylene than the 3.7°C measured for polyethylene.

Research paper thumbnail of Progress on Fast Analytical Temperature Rising Elution Fractionation (ATREF) Technique for Practical Applications

International Journal of Polymer Analysis and Characterization, 2014

ABSTRACT Fast analytical temperature rising elution fractionation (ATREF) is a recently proposed ... more ABSTRACT Fast analytical temperature rising elution fractionation (ATREF) is a recently proposed method to evaluate the molecular structure of polyolefins with unimodal distributions. In this article, we compare the results obtained by this method and the classical slow cooling rate ATREF. An interpretation of previous results found in the literature is proposed in order to explain one of the limitations usually associated with this technique. Practical recommendations are given to build columns adapted to this technique and to efficiently adjust the method parameters.

Research paper thumbnail of Elaboration of poly(lactic acid)/halloysite nanocomposites by means of water assisted extrusion: structure, mechanical properties and fire performance

RSC Adv., 2014

Poly(lactic acid) (PLA)/Halloysite nanotubes (HNTs) nanocomposites were prepared using a water as... more Poly(lactic acid) (PLA)/Halloysite nanotubes (HNTs) nanocomposites were prepared using a water assisted extrusion process. Morphology, structure, thermomechanical properties and fire performance of these nanocomposites were compared to those obtained in the case of nanocomposites elaborated via conventional extrusion process. Whatever the elaboration route used, mechanical tests indicate that HNTs have a reinforcing effect ascribed to the dispersion, at least partial, of the HNTs into the PLA matrix. Differential Scanning Calorimetry also shows that HNTs infers on the PLA crystallization and play the role of nucleating agent.

Research paper thumbnail of Anionic and ionic coordinative polymerization ofL-lactide

Polymers for Advanced Technologies, 1998

The potassium naphthalenide complex with 18-crown-6 is able to initiate anionic polymerization of... more The potassium naphthalenide complex with 18-crown-6 is able to initiate anionic polymerization of L-lactide at 20°C. This type of anionic initiator does not have to be removed from the polymer as it does not affect metabolic processes. The ionic polymerization of L-lactide with an ...

Research paper thumbnail of Copolymerization of the pair maleic anhydride-dicyclopentadiene: I. Copolymerization and post-copolymerization at high conversion

Polymer International, 2005

Dicyclopentadiene (DCPD) is one of the most accessible cyclo-olefins. Indeed, cyclopentadiene is ... more Dicyclopentadiene (DCPD) is one of the most accessible cyclo-olefins. Indeed, cyclopentadiene is present at concentrations of up to 20 % in commonly recovered fractions following pyrolysis of the crude oil C5. Its stable form (below 100 °C) is represented by the corresponding ...