Thermo‐Responsive and Emulsifying Properties of Poly(N‐vinylcaprolactam) Based Graft Copolymers

Abstract

Thermo‐responsive graft copolymers have been synthesized based on a poly(N‐vinylcaprolactam) (PVCL) backbone and either hydrophilic poly(ethylene oxide) (PEO) or hydrophobic poly(tetrahydrofuran) (PTHF) side chains. The phase separation behavior of the graft polymers in water was studied by transmittance measurements and compared to that of the corresponding swollen segmented polymer networks and aqueous solutions of both polymers. The influence of the concentration and length of the grafts on the cloud point temperature (TCP) has been demonstrated. PVCL‐g‐PTHF copolymers have been synthesized by using the macromonomer technique, i.e. the radical copolymerization of VCL with a PTHF macromonomer. A special feature of these amphiphilic graft copolymers is their ability to stabilize aqueous emulsions below the TCP and to suddenly break them above the TCP. PVCL‐g‐PEO copolymers were prepared by a grafting onto method. First, succinimide groups were introduced in the backbone, to which amino terminated PEO chains were grafted in the second step. This leads to di‐hydrophilic copolymers that become amphiphilic after heating their aqueous solutions above the TCP.

Fast, multi-responsive microgels based on photo-crosslinkable poly(2-(dimethylamino)ethyl methacrylate)

“…'s for 10 wt% polymer solutions in water decrease with increasing CPMA content, as expected from its hydrophobic character [27,28]. The signal in the DSC curve, which is a clear peak for poly(DMAEMA 99 -co-CPMA 1 ) and poly(DMAEMA 97.5 -co-CPMA 2.5 ), also becomes weaker and broader with increasing CPMA content, until no distinguishable maximum is observed for poly(DMAEMA 90 -co-CPMA 10 ).…”

Functional segmented polymer networks based on polytetrahydrofuran and poly(vinylbenzyl chloride)

“…Recently, a model study on PTHF bis-macromonomers and other co-monomers confirmed this hypothesis [23].…”

Polymer Thermo-Responsive Gate Membranes

“…pNIPAAm is an example for non ionic water soluble polymer showing this type of phase behaviour. Other examples for thermo-responsive polymers are poly (N-vinyl caprolactam) (PVCL) [7], poly (ethylene oxide) (PEO) [8], PDMAEMA and poly(2-ethyl-2-oxazoline) (PEtOx) [8]. The LCST of a polymer can be changed by copolymerization.…”