Characterization of Ethylene methyl methacrylate and Ethylene butylacrylate Copolymers with Interactive Liquid Chromatography

Yang

Macro Chemistry & Physics

et al. 2020

Regioselective addition of nonsymmetrical monomers in radical polymerization is a basic issue for control of the reaction kinetics and structure of the resulting products. In reversible addition‐fragmentation chain transfer (RAFT) polymerization, head addition generates primary alkyl adducts when trapped by RAFT agents. Due to the low leaving ability of primary alkyl radicals, this kind of adduct in RAFT polymerization will become nonactive macro‐RAFT agents, that is, dead dormant species (DDS). Based on the previously‐developed equation for the correlation of DDS content (α) with head‐addition incidence (ρ1) in RAFT polymerization and the quantitative determination method of DDS content by coupling a block‐polymerization derivatization with gradient polymer elution chromatography analysis, the ρ1 values of methyl acrylate (MA) at different temperatures are determined with benzyl N‐carbazolecarbodithioate (BCBD) as RAFT agent and 2‐methyloxyethyl acrylate as the second monomer for block‐polymerization derivatization. The results show that the ρ1 values of MA at 60, 70, 80, and 90 °C are 2.04 × 10−3, 2.37 × 10−3, 2.72 × 10−3, and 3.28 × 10−3, respectively, and the activation energy for ρ1 is 15.8 kJ mol−1. The DDS in BCBD‐mediated RAFT polymerization of MA is separated by column chromatography and characterized by 1H‐NMR and MALDI‐TOF MS.

Section: Resultsmentioning

confidence: 99%

Determination of Head‐Addition Incidence of Methyl Acrylate and Temperature Dependence in Radical Polymerization by Coupling Reversible Addition‐Fragmentation Chain Transfer Block Polymerization Derivatization and Gradient Polymer Elution Chromatography

Yang

Macro Chemistry & Physics

et al. 2020

J of Separation Science

“…Critical conditions were also determined for PS on silica gel using decalin and cyclohexanone at 1401C and applied to characterize ethylene-styrene block copolymers [88]. Albrecht and coworkers [56,[89][90][91][92] developed several chromatographic systems for the separation of EVA, ethylene-butylacrylate and EMA copolymers at 1401C, which ensure solubility of homopolymers as well as the copolymers. The units of the polar comonomers were adsorbed on silica gel from decalin or TCB, whereas the nonpolar units of methylene (i.e.…”

Section: Hplc Systems For the Separation Of Functionalized Olefin Copmentioning

confidence: 99%

“…Chitta et al . have shown that these admixtures falsified the values of the average chemical composition as determined by NMR spectroscopy 92. The conventional techniques such as CRYSTAF or DSC fail to detect these admixtures.…”

Section: Molecular Characterization Of Polyolefinsmentioning

confidence: 99%

“…Albrecht and coworkers 56, 89–92 developed several chromatographic systems for the separation of EVA, ethylene–butylacrylate and EMA copolymers at 140°C, which ensure solubility of homopolymers as well as the copolymers. The units of the polar comonomers were adsorbed on silica gel from decalin or TCB, whereas the nonpolar units of methylene ( i.e .…”

Section: Molecular Characterization Of Polyolefinsmentioning

confidence: 99%

See 1 more Smart Citation

A review on the development of liquid chromatography systems for polyolefins

Macko¹,

Brüll²,

Zhu

et al. 2010

Self Cite

Polyolefins are the most widely produced synthetic polymer commodity and are found in countless applications ranging from bottles, packaging films to bullet-proof jackets, etc. Such widely different applications rely on high variability in the physical properties of polyolefins, which is a result of variations in microstructure, chemical composition and molar mass. Though polyolefins contain only carbon (C) and hydrogen (H) atoms, the microstructures of polyolefins are extremely variable, differing in the nature of the monomers (e.g. ethylene versus propylene), the degree of branching, chemical composition in the case of copolymers and finally their molar masses. Production, research and development of polyolefins require the analysis of polyolefin samples in terms of all these parameters. Development of efficient and robust analytical techniques based on the interactive LC is reviewed. The needed computational/theoretical studies to understand the retention mechanism in the newly developed chromatography systems are discussed.

“…One approach to determine polymer end groups is using interactive polymer chromatography (IPC), in which retention in IPC is often dependent on the chemical composition, functionality, and molecular weight of the polymer. [12][13][14][15][16][17][18][19][20] More specifically, interaction gradient elution polymer chromatography (interactive GPEC). [17,[21][22][23] In interactive polymer LC, the retention is governed by the polymer interaction with the chemical groups of the chromatographic column's stationary phase, and the polarity and elution strength of the mobile phase.…”

Section: Introductionmentioning

confidence: 99%

Functionality-type and chemical-composition separation for poly(lactide-co-glycolide) using gradient elution with basic and acidic additives in normal-phase liquid chromatography

Serizawa,

Reekers,

Delft

et al. 2024

Preprint

The end groups of poly(lactide-co-glycolide) (PLGA) play a crucial role in determining the properties of polymers used in drug delivery systems. Research has shown that the encapsulation efficiency in PLGA microspheres can vary significantly between ester-terminated and acid-terminated PLGA. To study the functionality-type distribution (FTD) in PLGA polymers, researchers have used methods such as matrix-assisted laser desorption/ionization – high-resolution mass spectrometry and electrospray ionization – mass spectrometry. However, these methods are typically limited to PLGA polymers with a molecular weight of up to 4kDa. 13Carbon-nuclear-magnetic-resonance has also been used to differentiate and quantify PLGA end groups, but this method is time-consuming, taking over 12 hours per sample. To address these limitations, we have developed a normal-phase liquid chromatography method that can separate FTD and partial chemical composition distribution (CCD) in PLGA polymers. Our method can separate PLGA polymers with a molecular weight of up to 185 kDa and simultaneously separate the difference in lactic acid (LA)/glycolic acid (GA) ratios. To achieve this, we used a cross-linked diol column with a ternary gradient from hexane to 0.1% v/v triethylamine in THF to 0.1% v/v formic acid in THF. This allowed for the elution of ester-terminated PLGA, followed by acid-terminated PLGA. We also separated ester-terminated PLGA in the difference of the LA/GA ratio. Our method is expected to help understand the correlation between PLGA’s FTD, CCD, and physical properties, which will facilitate product development.