Plasticizer absorption

Other Measurements. Other tests include free moisture content, rate of dissolution and undissolved residue in acids and alkaH, resin and plasticizer absorption, suspension viscosity, and specific surface area. Test procedures for these properties are developed to satisfy appHcation-related specifications. 

Two types of the homopolymer are available, the flexible and the rigid. Both types have excellent chemical and abrasion resistance. The flexible types are produced with high porosity to permit plasticizer absorption. Articles made from the rigid type are hard and cannot be stretched more than 40% of their original length. An important property of PVC is that it is self-extinguishing due to presence of the chlorine atom. 

ISO 4574 1978 Plastics - PVC resins for general use - Determination of hot plasticizer absorption... 

Another method, the emulsion process, was developed in Europe to meet the demand for a resin with small particle size, high bulk density, and low plasticizer absorption properties. These characteristics are especially desirable in making plastisols and organosols, where the resins are dispersed in liquid plasticizers. In this polymerization process, emulsifiers are added, and the solution is agitated to keep the monomer droplets dispersed. The initiators must be water soluble it is usually an inorganic persulfate or an organic hyperperoxide. 

Wallace et al. (20) correlated GC retention volumes of several poly(vinyl chloride) powders with their uptake of plasticizer. Since the diffusion of plasticizers into polymer powders is controlled by the external surface area, the diffusion coefficient of the plasticizer and some shape factor, a correlation with GC measurements could be expected. It was found that plasticizer absorption ( drying ) took place only when the polymer was heated to a temperature immediately above the glass transition temperature as defined by the minimum of the experimental retention diagram. 

PVC is insoluble in VCM. The precipitated polymer tends to coagulate in the conversion range of 1-8%. As the conversion continues, the precipitated polymer absorbs more and more monomer, and at a 15-20% conversion, the reactor contains solid polymer swollen with monomer in a monomer atmosphere. The horizontal autoclave prevents the formation of large polymer blocks by breaking them up. Advantages claimed for this process are the higher bulk density, improved particle size distribution, and more rapid plasticizer absorption. Talamini and coworkers (J ) have demonstrated that the bulk polymerization process is kinetically equivalent to suspension polymerization. 

Plasticizer Absorption—The ability of a resin to absorb plasticizers depends on particle size and distribution, particle surface characteristics, and particle porosity. Highly absorptive resins, which generally have high particle porosity and irregular shapes, provide faster drying and minimum dry-blend time cycles,... 

Special properties good gelation, high apparent density, high brilliance, high plasticizer absorption, low fish-eye content, matt finish, narrow particle size distribution, transparency ... 

The thickness of coating is controlled by the particle size of PVC. T ical coating thickness is 254-457 im. Most of the powder coating using PVC (90%) is done in North America. Standard types of suspension PVC are not suitable for this t) e of processing because membranes of resin particles interfere with plasticizer absorption and cause an increase in fusion temperature and thus increase the risk of thermal degradation. ... 

Special properties air release, antiblocking, matting agent, Newtonian flow, processing aid, rapid plasticizer absorption, transparency ... 

Special properties rapid and extensive plasticizer absorption ... 

Figure 2.20. Cold plasticizer absorption vs. polymerization temperature. [Data from Bao, Y. Z. Brooks, B. Vi.,J.Appl. Polym. Set, 85,1544-1552,2002.]...

Inorganic antiblocking additives are frequently added in concentrations larger than required because they perform other functions, such as surface matting and plasticizer absorption. 

Wong, S., Shanks, R.A. and Hodzic, A. (2003) Poly(L-lactic acid) composites with flax fibers modified by plasticizer absorption. Polymer Engineering Science, 43, 1566-1575. 

Distearyl thiodipropionate Ditridecyl thiodipropionate Poly-a-methylstyrene Trixylenyl phosphate plasticizer, absorption bases Lanolin alcohol plasticizer, ABS-PC Triphenyl phosphate plasticizer, acrylate elastomers Triisononyl trimellitate plasticizer, acrylate resins Diisooctyl phthalate plasticizer, acrylic coatings Benzyl phthalate Butyl benzyl phthalate Polypropylene glycol dibenzoate plasticizer, acrylic latex 2-Pyrrolidone... 

Designation system was developed for vinyl chloride thermoplastic resins which may be used as the basis of specification. In respect to plasticizers, the system allows to include in specification, plasticizer absorption at room temperature, viscosity of paste, and rheological behavior of paste. The second part of ISO standard gives a list of ISO standards used for testing of properties included in designation system and describes preparation of sample. 

BS EN ISO 4608 1998, BS 2782-4 Method 454E 1998 Plastics. Homopolymer and copolymer resins of vinyl chloride for general use. Determination of plasticizer absorption at room temperature... 

ISO 3826 1993 Plastics collapsible containers for human blood and blood components ISO 4574 1978 Plastics — PVC resins for general use — Determination of hot plasticizer absorption ISO 4575 1985 Plastics — Polyvinyl chloride pastes — Determination of apparent viscosity using the Severs rheometer... 

PN-93/C-89291.29 Plastics - PVC resins for general use - Determination of hot plasticizer absorption PN-EN ISO 176 2002 (U) Plastics - Determination of loss of plasticizers - Activated carbon method (ISO 176 1976)... 

There are also indirect methods for evalnating compatibility including the rate of plasticizer absorption, conductivity measurement, thermomechanical, optical, NMR, calorimetry,and dielcometry. 2 ... 

Figure 7.11. Kinetics of plasticizer absorption by SKN-26 and SKDU samples at 25°C in SKN-26/PDU (1) and SKDU/SKI (2) systems.

Henschel mixer is most frequently used for dryblending. " In such a mixer, the technological process includes addition steps and temperatures which must be reached in order to proceed to the next step. Order of addition is considered important. The following order of addition is usually suggested resin, stabilizer, plasticizer, filler, lubricant. Stabilizer is added to the resin before it is subjected to heat, and lubricant is added at the end because it may interfere with plasticizer absorption. - Temperatures which determine the end of the mixing step depend on the amount of plasticizer in a mixture (the higher the amount of plasticizer, the higher the temperature). Final temperature of dryblend is between 90 and 110°C. Premixed dry blend is then cooled to below 50°C. ... 

Linek.V., Stoy.V., Machon.V. and Z.Krivsky. "Increasing the effective interfacial area in plastic absorption columns". Chem.Engng.Sci. 29 (1974) 1955. 

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