Pre-polymer molecule

Pre-polymer molecule A pre-polymer molecule is a polymer or oligomer molecule that can enter into subsequent polymerization. Polyester and epoxy resins are made by reacting prepolymers with cross-iinking molecules, frequently also oligomers. ... 

A polymer is joined to itself by cementing with a solution of the same polymer in a volatile solvent. The solvent softens the surfaces, and the dissolved polymer molecules bond them together. Components can be joined by monomer-cementing the surfaces are coated with monomer which polymerises onto the pre-existing polymer chains, creating a bond. 

Terminally unsaturated structures are formed as in reactions 1, 5 and 7 and it is to these that thermal destabilization due to pre-irradiation must be attributed. It is well established that unsaturated structures in polymer molecules constitute thermally labile or "weak" links because the energy requirement for scission at adjacent bonds is reduced by approximately 19 k cal mole", being the energy associated vrLth the allyllc radical thus formed. 

At this stage, one can raise the question as to whether the fibrils observed with AFM are micelles pre-formed in solution that deposit on the substrate as the solvent evaporates, or assemblies forming upon adsorption of the polymer molecules on the substrate. As mentioned above, the preparation... 

A widely accepted hypothesis of the mechanism responsible for drag reduction is that the microscale eddies in the bufferzone of the turbulent boundary layer are suppressed. It is thought that the macromolecules (injected or pre-mixed) affect the sublayer instability which produces jet-like vortices, the so-called "bursts", which erupt into the boundary layer and lead to the production of much turbulent energy. Recent experiments have shown [l] that the polymer molecules seem to act as a "barrier" restricting communication across the boundary layer so that the fluid near the wall flows in a more laminar manner [2]. 

The QELS and adsorption studies of competitive adsorption and aggregation of macromolecules/ NP for polymers (PVP, PEG, PVA), gelatin, ovalbumin or BSA, and nanosilica are in agreement with the QCM data with respect to the effects of surface roughness, confinement space in pores, and the characteristics of macromolecules and their interactions in pre-adsorbed macromolecules and with partially coated solid surfaces. Proteins can more effectively displace smaller polymer molecules if the latter have only electron-donor groups (PEG, PVP). In the case of a pre-adsorbed... 

Oxidative phenolic cross-linking of polymer molecules at pre-existing reactive sites is a mechanism common to many biological systems. The two types of cross-links which form are shown in Fig. 14. The symbol R represents the connection between the phenolic group and the polymer which carries it. 

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