Low temperature RAFT/MADIX gel polymerisation: access to controlled ultra-high molar mass polyacrylamides

Poly(N‐isopropylacrylamid)‐Phasendiagramme: 50 Jahre Forschung

“…Halperin et al 70 8 8Ci ne inem Lçsungsmittel wie 1,4-Dioxan durchgeführt. Angesichts der kürzlich bekannt gewordenen Herstellung von Polyacrylamid mit M n % 106 kDa bei gleichzeitig niedrigem PDI < 1.2 durch einen RAFT/MADIX-Prozess ("Macromolecular Design by Interchange of Xanthates"), [93] bei dem Xanthate (R-O-C( = S)-S-R;Schema 2) als CTAf ungieren, [94] mag sich das aber ändern. Okamoto et al [92] demonstrierten in einer Studie,dass man eine gleichzeitige Kontrolle der Taktizität und der Molmasse von PNIPAM durch Hinzufügen eines geeigneten Katalysators,e twa Yttriumtriflat [Y(OTf) 3 ], zu der Polymerisationsmischung erreichen kann.…”

A synthetic route to ultra-high molecular weight polystyrene (>106) with narrow molecular weight distribution by emulsifier-free, emulsion organotellurium-mediated living radical polymerization (emulsion TERP)

“…The upper limit of the MW of synthetic polymers is decided by the side reactions (mainly by the termination reaction). 16 Matyjaszewski et al proposed an activator regenerated by electron transfer (ARGET) ATRP, 17 in which a pseudo-halide initiator decreased the side reaction between the radical species and the copper catalyst and improved the livingness of the polymer chains, resulting in an ultra-high MW (M n ∼ 1.17 × 10 6 ) PMMA with a narrow MWD ( polydispersity index (PDI) = weight-average molecular weight (M w )/ M n ∼ 1.2). In 2002, Agarwal et al synthesized a moderately-high MW (number-average molecular weight (M n ) ∼ 3.67 × 10 5 ) poly(methyl methacrylate) (PMMA) by atom transfer radical polymerization (ATRP).…”

Hybrid polyion complex micelles from poly(vinylphosphonic acid)-based double hydrophilic block copolymers and divalent transition metal ions

“…The relevant values of dn/dc in this eluent are: 0.151 ml g À1 (PAA) and 0.185 ml g À1 (PAm) [58]. The dn/dc of block copolymers were calculated from the average of the dn/dc of the constituent homopolymers, weighted according to their mass fraction.…”