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Department of Chemistry
Hornluftdosierung an einer Spritzpistole im Praktikum Lackapplikation Show image information
Kolorierte Rasterelektronenmikroskopaufnahme eines Effektpigmentes Show image information
Mittels des PeakForce QNM-Messmodus lassen sich nanomechanische Eigenschaften am Rasterkraftmikroskop ermitteln. Show image information
Kolorierte Rasterelektronenmikroskopaufnahme einer mmonodispersen Polymerdispersion Show image information
Probenwechsel unter dem Infrarotstrahler Show image information
Ermittlung der Kornfeinheit mittels Grindometer im Praktikum Show image information

Hornluftdosierung an einer Spritzpistole im Praktikum Lackapplikation

Photo: Irina Regehr, CMP, Universität Paderborn

Kolorierte Rasterelektronenmikroskopaufnahme eines Effektpigmentes

Photo: Nadine Buitkamp, CMP, Universität Paderborn

Mittels des PeakForce QNM-Messmodus lassen sich nanomechanische Eigenschaften am Rasterkraftmikroskop ermitteln.

Photo: Irina Regehr, CMP, Universität Paderborn

Kolorierte Rasterelektronenmikroskopaufnahme einer mmonodispersen Polymerdispersion

Photo: Nadine Buitkamp, CMP, Universität Paderborn

Probenwechsel unter dem Infrarotstrahler

Photo: Irina Regehr, CMP, Universität Paderborn

Ermittlung der Kornfeinheit mittels Grindometer im Praktikum

Photo: Irina Regehr, CMP, Universität Paderborn

Coating Materials & Polymers
Prof. Dr. Wolfgang Bremser

DPE dispersions

The water-based Controlled Radical Polymerization (CRP) has been one of the fastest growing fields of interest in polymer research for the past decades. "Nitroxide mediated polymerization" (NMP), "atomic transfer radical polymerization" (ATRP) and "reversible addition fragmentation chain transfer" (RAFT) are the most common methods used today. Besides these, a method was developed using 1,1-Diphenylethylene (DPE).

The synthesis of emulgator-, metall-, additive- and solvent free waterborne dispersions is possible with the DPE-method.

The mechanism

With the DPE-method, block copolymers are synthesized in a two step process. In the first step an oligomeric, hydrophilic precursor is synthesized from hydrophilic monomers (like acrylates, methacrylates and methylmethacrylates), 1,1-Diphenylethylene and an peroxodisulfate initiator.

Structure of the hydrophilic precursor showing a dimeric a,p-DPE-structure, consisting of polar monomers.

This precursor is the stabilizing agent for the second step of synthesis, in which non polar monomers (like (meth)acrylates, styrene) are added to the hydrophilic segment in an addition-fragmentation-mechanism. The forming amphiphilic block copolymers directly aggregate to micells with a diameter of roughly 10 nm that will further grow to about 50 to 150 nm when adding additional monomer.

TEM picture of DPE dispersion particles

Non-conventional core-shell-structured block copolymers are accessible through this method.

These copolymers are showing application-technological interesting properties:

  • The film formation occurs considerably beneath the glass transition temperature, so DPE block copolymers can be used for solvent free coating or adhesive systems.
  • The functionalized dispersion particles can be locally deposited onto galvanized substrates to realize a better corrosion protection.
  • Through their micellular structure the nucleation and the growth of calcium carbonate and barium sulfate nanoparticles can be controlled. Different particle morphologies and mineral hollow spheres can be produced.

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