Beschreibung:
<jats:p>Multiblock structured glucan ethers are prepared for the first time by BF<jats:sub>3</jats:sub>·OEt<jats:sub>2</jats:sub> promoted transglycosidation of two cellulose ether homopolymers. First, model studies are performed with equimolar mixtures of methyl cellulose (MC) and deuteromethyl cellulose (MC‐<jats:italic>d</jats:italic><jats:sub>3</jats:sub>), varying the amount of Lewis acid and temperature. Reaction is monitored by <jats:sup>1</jats:sup>H NMR spectroscopy and electrospray ionization mass spectrometry after partial hydrolysis of products. Cross reaction is proved and the decrease of average block length with time is monitored and found to approximate random distribution. The method is successfully applied to a mixture of ethyl cellulose and MC. Decreases of molecular weight, of dispersity, and of glass transition temperature <jats:italic>T</jats:italic><jats:sub>g</jats:sub> with reaction time are followed.
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