3.2.1 Analysis of Ethylene-Methyl Acrylate Copolymers [40]
3.2.1.1 Aim
Commercial interest in copolymers of ethylene and methyl acrylate (MA) is
increasing due to its various applications, e.g. the production of films, foams or
hot melt adhesives (depending upon their comonomer contents). As is true for all
copolymers, ethylene-methyl acrylate (EMA) copolymers exhibit MMD and CCD.
For the optimization of synthetic procedures and the development of structure–
property correlations, a comprehensive characterization of these copolymers is
required. EMA copolymers with low MA contents may be semi-crystalline
materials that can be separated according to composition by TREF or CRYSTAF.
With higher MA contents, the materials are fully amorphous and thus cannot be
separated by crystallization-based techniques. It is, therefore, the aim of the present
application to separate EMA copolymers irrespective of crystallinity by HT-HPLC.
Quantitative chemical compositions shall be determined by FTIR spectroscopy.
3.2.1.2 Materials
• Calibration standards. Linear PE standards (PSS GmbH, Mainz, Germany)
• Polymers. EMA copolymers were obtained from Exxon Mobil Chemical
(Meerhout, Belgium), Du Pont (Geneva, Switzerland) and Arkema (Paris,
France). Their characteristics are summarized in Table 3.3.
3.2.1.3 Equipment
• Chromatographic system. PL XT-220 (Polymer Laboratories, Varian Inc,
Church Stretton, England) was used as the high-temperature gradient HPLC
system. A robotic sample handling system PL-XTR (Polymer Laboratories) was
used for dissolution and injection at higher temperature. The temperature of the
whole system, comprising the sample block, injection needle, injection port and
the transfer line between the auto sampler and the column compartment, was set
to 140
C. The flow rate was set to 1 mL/min. The dissolution time was 2 h to
ensure complete dissolution of the samples.
• Columns. Perfectsil 300 A ˚ (particle diameter 5 μm, pore volume 1.05 mL/g, void
volume V 0 ¼ 3.21 mL) and Polygosil 1,000 A ˚ (particle diameter 10 μm,
V 0 ¼ 3.15 mL) (MZ Analysentechnik, Mainz, Germany). Column size
250 mm  4.6 mm i.d.
• Mobile phase. Decalin-cyclohexanone.
• Detectors. ELSD PL-ELS 1000 (Polymer Laboratories, Church Stretton,
England). An air flow rate of 1.5 L/min, a nebulizer temperature of 160
C and
an evaporator temperature of 270
C were set on the ELSD. The LC-Transform
FTIR interface (Series 300, Lab Connections, Carrboro, USA) was used. The
settings of the LC-Transform were stage temperature of 150
C, nozzle temperature of 139
C and rotation speed of germanium disc of 10
per minute. A
Nicolet Protege ` 460 (Thermo Electron, Waltham, USA) was used for FTIR
spectroscopy of the deposited sample fractions. WinGPC-Software (Polymer
96
3 Column-Based Chromatographic Techniques
3.2.1.1 Aim
Commercial interest in copolymers of ethylene and methyl acrylate (MA) is
increasing due to its various applications, e.g. the production of films, foams or
hot melt adhesives (depending upon their comonomer contents). As is true for all
copolymers, ethylene-methyl acrylate (EMA) copolymers exhibit MMD and CCD.
For the optimization of synthetic procedures and the development of structure–
property correlations, a comprehensive characterization of these copolymers is
required. EMA copolymers with low MA contents may be semi-crystalline
materials that can be separated according to composition by TREF or CRYSTAF.
With higher MA contents, the materials are fully amorphous and thus cannot be
separated by crystallization-based techniques. It is, therefore, the aim of the present
application to separate EMA copolymers irrespective of crystallinity by HT-HPLC.
Quantitative chemical compositions shall be determined by FTIR spectroscopy.
3.2.1.2 Materials
• Calibration standards. Linear PE standards (PSS GmbH, Mainz, Germany)
• Polymers. EMA copolymers were obtained from Exxon Mobil Chemical
(Meerhout, Belgium), Du Pont (Geneva, Switzerland) and Arkema (Paris,
France). Their characteristics are summarized in Table 3.3.
3.2.1.3 Equipment
• Chromatographic system. PL XT-220 (Polymer Laboratories, Varian Inc,
Church Stretton, England) was used as the high-temperature gradient HPLC
system. A robotic sample handling system PL-XTR (Polymer Laboratories) was
used for dissolution and injection at higher temperature. The temperature of the
whole system, comprising the sample block, injection needle, injection port and
the transfer line between the auto sampler and the column compartment, was set
to 140
C. The flow rate was set to 1 mL/min. The dissolution time was 2 h to
ensure complete dissolution of the samples.
• Columns. Perfectsil 300 A ˚ (particle diameter 5 μm, pore volume 1.05 mL/g, void
volume V 0 ¼ 3.21 mL) and Polygosil 1,000 A ˚ (particle diameter 10 μm,
V 0 ¼ 3.15 mL) (MZ Analysentechnik, Mainz, Germany). Column size
250 mm  4.6 mm i.d.
• Mobile phase. Decalin-cyclohexanone.
• Detectors. ELSD PL-ELS 1000 (Polymer Laboratories, Church Stretton,
England). An air flow rate of 1.5 L/min, a nebulizer temperature of 160
C and
an evaporator temperature of 270
C were set on the ELSD. The LC-Transform
FTIR interface (Series 300, Lab Connections, Carrboro, USA) was used. The
settings of the LC-Transform were stage temperature of 150
C, nozzle temperature of 139
C and rotation speed of germanium disc of 10
per minute. A
Nicolet Protege ` 460 (Thermo Electron, Waltham, USA) was used for FTIR
spectroscopy of the deposited sample fractions. WinGPC-Software (Polymer
96
3 Column-Based Chromatographic Techniques