Polymer-compounding, process

Figure 5.2 Flow sheet of polymer compounding process.

Fritz, H.G. and Stoehrer, B. (1986) Polymer compounding process for controlled peroxide-degradation of polypropylene. Int. Polymer Processing, 1, 31-41. 

Shih, C. K., Fundamentals of polymer compounding Part II simulation of polymer compounding process, 49th ANTEC, Montreal, SPE, 99 (1991). 

Accelerator activators are chemicals required to initiate the acceleration of the curing process. They also improve the polymer compound quaUty. 

Flame Retardants. Bromine compounds make up an important segment of the market for flame retardants used in polymers. Additive flame retardants are added to polymers during processing reactive flame retardants react chemically to become part of the polymer chain itself. In addition to the compounds Hsted in Table 3, a number of proprietary mixtures and phosphoms—bromine-containing flame retardants are also sold (see Elame RETARDANTS, HALOGENATED, FLAAffi RETARDANTS). 

Polymer compounds vary considerably in the amount of heat required to bring them up to processing temperatures. These differences arise not so much as a result of differing processing temperatures but because of different specific heats. Crystalline polymers additionally have a latent heat of fusion of the crystalline structure which has to be taken into account. 

As has been mentioned in earlier chapters polymers vary enormously in their thermal stability. Before attempting to process any specific polymer compound its thermal stability characteristics should be considered. The most important questions to be answered are ... 

At the present time, the difficulty is correlating incoming raw ingredient properties with processability. Elastomeric compounds can be considered to be made up of four components polymers, fillers, process aids, and other chemicals. 

Therefore, if processability is to be measured on a regular basis, it would be extremely useful if a piece of equipment was available that could measure the dynamic properties under realistic operating conditions. Fortunately, one piece of test equipment has been developed, which is commercially available, the RPA 2000 (Monsanto Co.), which may meet the requirements. A considerable number of investigations have been reported on the RPA 2000 [2J, that support the view that it may meet the requirements of an instrument that measures both polymer and compound processability. The work to date identifies differences in polymers and compounds. However, it is important to relate those differences to processing characteristics in the manufacturing environment. 

What type of feeding system is required to incorporate a low viscosity fluid into a high molecular weight polymer What issues might arise during the compounding process due to the form of the additive ... 

Report 78 PVC - Compounds, Processing and Applications, J.Leadbitter, J.A. Day, J.L. Ryan, Hydro Polymers Ltd. 

The addition rate of the Dessicante masterbatch is typically 1.0-3.0%. Approximately 1 % addition of the PE 48/10/96 masterbatch will remove 0.1 % of water from the polymer during the extrusion or compounding process. 

One of the complexities in the direct study of the PMR cure is the superposition of monomer isomerization on the polymerization chemistry of interest. To ensure our ability to dissect these two kinds of processes, we first studied the thermal behavior of each of our model compounds in the absence of any polymer forming process in dilute solution. 

A former having roughly the shape of the article to be moulded is immersed in a suitable liquid compound that forms a deposit onto the former, which is possibly heated to ease the increase in thickness of the deposit. The former can be first sheathed with a knitted fabric to reinforce the dipped polymer. This process is used in special cases ... 

TPS can be used for the real-time monitoring of polymeric compounding processes as demonstrated by Krumbholz et An industrial hardened terahertz spectrometer was interfaced with a polymer extruder, allowing for real-time measurement of the additive content in molten polymers (Figure 16.3). 

Generally, only the interstitial metal ions Mb) can diffuse through the solid polymer compounds. So far, the other metal ions have not been shown to diffuse, although very slow processes of diffusion, especially... 

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