Resin rheology

Finally, the viscosity P can be described by Equations 5.42 or 5.43, depending on whether a Newtonian or a generalized Newtonian viscosity model is required to describe the resin rheology. 

Optical properties Clarity measured as a haze value is an obvious critical attribute, though haze values should be compared only for a specific sample thickness and for a specific resin rheology (eg, melt flow rate). Optical measurements may also include molded plaque gloss or internal gloss, for containers. 

The production of oriented PP slit tapes is complicated by the tape s tendency to split or fibrillate randomly into tiny fibrils, damaging the quality of the final woven tape product. Typically, HOPE or calcium carbonate additions are used to fight random fibrillation, but these can change the resin rheology and/or reduce the "hand feel" quality of the woven tape. One additive... 

Pyrogenic silica is normally used in amounts smaller than 1 wt% in order to control the resin rheological behavior. However, for scratch-resistant coating systems the... 

Resin Rheology (binder to improve green strength) Ethyl cellulose... 

In order to evaluate the rotomoldability of the selected resins rheological, thermal characterization, sintering and surface tension tests were conducted. The material characterization was followed by a series of rotational molding experiments. The molded parts were evaluated in tensile tests. 

Suspension- and emulsion-polymerized PVDF exhibit dissimilar behavior in solutions. The suspension resin type is readily soluble in many solvents even in good solvents, solutions of the emulsion resin type contain fractions of microgel, which contain more head-to-head chain defects than the soluble fraction of the resin (116). Concentrated solutions (15 wt %) and melt rheology of various PVDF types also display different behavior (132). The Mark-Houwink relation (rj = KM°-) for PVDF in A/-methylpyrrohdinone (NMP) containing 0.1 molar LiBr at 85°C, for the suspension (115) and emulsion... 

Molecular Weight. The range of molecular weights of commercial LLDPE resias is relatively narrow, usually from 50,000 to 200,000. One accepted parameter that relates to the resin molecular weight is the melt index, a rheological parameter which, broadly defined, is inversely proportional to molecular weight. A typical melt index range for LLDPE resias is from 0.1 to 5.0, but can reach over 30 for some appHcations. 

Rheology. Both PB and PMP melts exhibit strong non-Newtonian behavior thek apparent melt viscosity decreases with an increase in shear stress (27,28). Melt viscosities of both resins depend on temperature (24,27). The activation energy for PB viscous flow is 46 kj /mol (11 kcal/mol) (39), and for PMP, 77 kJ/mol (18.4 kcal/mol) (28). Equipment used for PP processing is usually suitable for PB and PMP processing as well however, adjustments in the processing conditions must be made to account for the differences in melt temperatures and rheology. 

Many different combinations of surfactant and protective coUoid are used in emulsion polymerizations of vinyl acetate as stabilizers. The properties of the emulsion and the polymeric film depend to a large extent on the identity and quantity of the stabilizers. The choice of stabilizer affects the mean and distribution of particle size which affects the rheology and film formation. The stabilizer system also impacts the stabiUty of the emulsion to mechanical shear, temperature change, and compounding. Characteristics of the coalesced resin affected by the stabilizer include tack, smoothness, opacity, water resistance, and film strength (41,42). 

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