Poly torque

Oil-Based SINs. The SINs produced were based on a castor oil polyester-urethane and styrene crosslinked with 1 mole percent of technical grade (55%) divinyl benzene (DVB) (7). This structure may be written poly[(castor oil, sebacic acid, TDI)-SIN-(Styfene, DVB)], poly[(CO,SA,TDI)-SIN-(S,DVB)]. Benzoyl peroxide (BP) (0.48%) was used as the free radical initiator for the styrene and 1,4-tolylene-diisocyanate (TDI) was used as the crosslinker for the polyester prepolymer. A 500 ml resin kettle equipped with a N inlet, condenser, thermometer, and high torque stirrer was used as the polymerization reactor. 

The apparent partial reversion of the polymerizing mixture after torque peaking, its dependence on shortstop concentration, and its ultimate decline with polymerization time are interesting phenomena. The desired shortstopping chemistry is pictured in Equation 3. It involves the reaction of the hydroxyl group of the added 1-propanol shortstop molecules with the unreacted terminal isocyanate groups on the poly(ester-urethane) chains. This permanently stops chain growth as desired. 

PA-6 (100-0) + poly(m-xylene adipamide) (0-100) / SEES (0-20) / SEBS-g-MA (1.8% MA) (0-20) SSE at 260°C / torque rheometry / mechanical properties / ductile-brittle transition temp. / TEM / DMTA / DSC / effects of mixing protocol / effects of PA-PA transamidation on properties Takeia et al., 1992a... 

ASTM D2396-94. Powder mix time of poly(vinyl chloride) (PVC) resins using a torque rheometer. 

Hegler R P Mennig G and Weber G. Kunststoffe 73 No7 353-357 (1983) (eng. transi. 9-11) ASTM D2538-95, Practice for fusion of poly(vinyl chloride) (PVC) compounds using a torque rheometer. 

ASTM D2538-02 Standard Practice for Fusion of Poly(Vinyl Chloride) (PVC) Compounds Using a Torque... 

Several materials were blended with PVC and properties of blends were compared with effect of plasticization by DOP. These included nitrile rubber, NBR, poly(ethylene-co-vinyl acetate), EVA, and poly(ethylene-co-vutyl aciylate-aciylate), Ac. Increase in plasticizer concentration (DOP) normally reduces torque and final melt temperature of blend but this is not the case when NBR replaces plasticizer. EVA behaves in a similar... 

Poly(lactic acid)/poly (butylene succinate) Melt blended/torque rheometry/SEM/ mechanical properties/TPPite catalyst Ojijo et al. 2013... 

Poly(lactic acid)/PB-f-epoxide/PP Haake mixer/torque rheology/DSC/ comparison to blend without PB-f-epoxide or with unfimctionalized PB Li et al. 2012b... 

The torque variation of blends during compounding can also indicate effect of MDI distribution. As expected, the addition of MDI increased the torque of pure PLA, due to molecular weight increase [45]. Similar results for other polyesters such as polycaprolactone (PCL) and poly(butyl-ene succinate adipate) (PBSB) have also been observed [44]. The highest torque values were recorded for the blends where MDI was distributed in the PLA phase, which further confirms the benefits of PLA phase distribution of MDI. The results of a detailed study of the rheological properties of the various blends will be reported in a separate paper. 

As described above in the section on morphology development, there are several separate mechanisms responsible for the effects of the interfacial reaction on the final morphology. Empirical means may be used to separate some of these simultaneous effects. For example, Scott and Macosko [41] successfully separated the effects of increased mixing torque and changing component rheologies as a fimction of temperature from other effects of the chemical reaction. They utilized Wu s [55] empirical equation for rubber particle diameters in reactive blends with polyamide 66 and poly(ethylene terephthalate) prepared in twin screw extruders ... 

Shear modulus versus time after a step strain for a poly-dimethylsiloxane. The inset graph shows that the commanded strain is reached in 3ms. Stress reaches a maximum in 6ms due to transducer inertia. Low torque signal and transducer hysteresis are limiting at long time. 

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