Plasticizer distribution

The pressure of the extmder forces uniform plastic distribution throughout the mold. Cooling the mold solidifies the plastic with slight shrinkage. The mold is maintained closed by mechanical or hydraulic pressure while the thermoplastic is injected and solidified. 

Chemicals Plastics, Distribution Distribution-Nondurable Goods Petroleum Products (except Bulk Stations/Terminals) Distribution Pipelines... 

The tension testing results of two typical FGMs in different parts along the direction of gradation are shown in Figures 5 and 6, respectively. Number 1, 2, 3, 4, 5 represent different parts of specimen used for test from inner to outer surface. In TiC particles reinforced FGM, with the increase of concentration, the strength and plasticity distribute gradiently. In the... 

Figure 1. Log-normal distributions used to create a bimodal-distribution model of a hypothetical rubber-toughened plastic. Distribution 1 2.0-pm average diameter, 0.4-pm standard deviation. Distribution 2 8.0-pm average diameter 0.8-pm standard deviation.

Figure 1.9 Plastic distribution by resin corresponding to MSW in Western Europe (1996).2...

These simple examples included only polymer and plasticizer. In normal formulations many other components exist and interact. Many studies address this subject in order to determine how to limit plasticizer loss. Montmorillonite clay was used as filler in PVC/ PMMA composite. The filler was used in its original and intercalated form to make polymer hybrid in which filler is dispersed on a molecular level. Totally different behavior was observed when composites were immersed in a solvent plasticizer mixture followed by drying. The sample containing the intercalated filler absorbed 50% less plasticizer than did any other sample studied. Thus plasticizer movement may be restricted by other than chemical interaction. These include physical obstacles in migration pathways that can also influence plasticizer distribution in a matrix. 

Polymer heterogeneity may also affect plasticizer distribution. Cellulose ititrate is heterogeneous because of the nature of cellulose and the heterogeneous mode of nitration. This results in formation of domains with lower degree of ititration. The study shows that plasticizer distribution was affected by the degree of nitration. 

Finally, the mixing process has a pronounced effect on plasticizer distribution and thus on the properties of plasticized mateiials. " " Preblending or multistage processes were developed to increase the homogeneity of plasticized materials. Improved mixing affects not only physical distribution of the plasticizer but also facilitates its interaction with the matrix polymer. This can be seen from the improved retention of plasticizer after extraction with various solvents. ... 

At ambient and processing temperatures, elastomers are viscous fluids with persistent transport phenomenon. In immiscible blends, these lead to change in the size and shape of the elastomer phases and migration of the fillers, plasticizers, and curatives from one phase to another. These changes are accelerated by processing and plasticization but retarded by the ultimate vulcanization. Retention of the favorable properties of a metastable blend, which is often attained only at a select interphase morphology and filler/plasticizer distribution, thus requires careful control of both the processing and the vulcanization procedures. 

Although the progress of the chemical industry has been toward con tinuous processes, some reactions will inevitably be conducted batchwise. The bulk of commercial batch reactions are polymerizations involved in the production of rubber and many types of plastics. Distribution of molecular weight is an important parameter in polymer manufacture, and it seems to be the most easily controlled batchwise. Another consideration is the great change in viscosity frequently encountered between the reactants and products. 

Beam-column elements Concentrated plasticity Distributed plasticity Fiber elements Lumped plasticity... 

---