Partial gelation

Wj fraction of resin at the stage b (absorption of plasticizer) Wj fraction of resin at a stage 0 (partial gelation)... 

Figure 16.7. Stages of gelation and fusion processes, a. mixture of PVC and plasticizer - plastisol b. particles absorbed plasticizer, have been swollen, and viscosity has been increased c. partial gelation accompanied with further viscosity increase, swelling and dissolving - borders of individual particles are still visible d. fused state. [Adapted, by permission, from Marcilla A Garcia J C, Eur. Polym. J., 33, No.3, March 1997, p.357-63.]...

Seeds n. Undesirable particles which develop in a liquid coating by partial gelation of the vehicle or by agglomeration of pigment particles. 

The granulation process included generating sol droplets by the droppers, shaping and partially gelating the droplets into spherical wet-gel granules in a paraffin oil layer, and consolidating the structure of the wet-gel granules in a 8 wt.% ammonia solution layer. The device used to prepare the gel particles is schematically shown in Fig.7. The temperature of the paraffin oil layer (white... 

The droplets generated from the dropper usually were not perfectly spherical, but they would gradually become good spheres while falling through the hot oil layer. This is basically because the immiscibility between the boehmite sol and the paraffin oil makes the spherical shape thermodynamically most stable. At the meantime when the droplets changed to spheres, partial gelation of the thin outer layer of the droplets occurred due to the increase of temperature. The... 

As little as 0.1% borax, based on solution weight, can cause thermally irreversible gelation. Boric acid forms a weaker monodiol complex and is preferred for controlled, partial gelation of PVOH. The reaction is very sensitive to / H, and full gelation occurs above pH 6. 

The polymerization was carried out with 1 g of the monomer and 2 mL of 13-dimethylimidazolidone under microwave irradiation for 2 min. An endothemic peak temperature determined by DTA at a heating rate of 10 C/min in nitrogen. Measured at a concentration of 0.5 g/dL in concentrated sulfuric acid at 30 C. A partial gelation occurred and the... 

The result of this complex system of reversible and irreversible side reactions is the simultaneous consumption and partial recovery of both components of the initiation system, a reduction in its activity, the formation of irregular (thermally or hydrolytically instable) stractures in polymer chains, and last-but not least-the creation of branched stractures. Such branching leads, in the case of multifunctional activators, to partial gelation. 

PVC Fusion (Gelation). The PVC piimaiy particle flow units (biUion molecule bundles) can partially melt, freeing some molecules of PVC... 

Cationic polyacrylamide may be used in the initial treatment stages to promote rapid polymer adsorption (201). Adjustment of the pH may allow deeper penetration of the fluids in an aluminate crosslinking system prior to gelation (202). A process involving injection of alternate slugs of stoichiometrically equivalent amounts of partially hydrolyzed polyacrylamide and Al O ) has been evaluated in the laboratory permeability of sana packs were reduced by more than 96% (203). Mixtures of Al(IIl) and Zr(IV) have also been evaluated as partially hydrolyzed polyacrylamide crosslinkers (204). 

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