Filled and unfilled samples

Additional samples included five replicates at each heating time without applying US vibrations. These were produced from both glass-filled and unfilled samples. Weld samples were also created between both the filled and unfilled samples. These samples were used for cross-sectioning and microtoming. Figure 2 shows a close-up of a typical sample being welded. 

The steady shear viscosities of the filled and unfilled samples were measured using a stress-controlled rheometers, MCR 500 from Anton Parr with 25mm plate-plate fixture at low shear rate range. A capillary rheometer, Rheograph 2003 from Goettfert was used at high shear rate range. The capillary with 1 mm diameter and L/D = 30/1 was used. 

Figure 8.1 Comparison of DMA data obtained for 30 % glass-filled and unfilled PBT samples...

The samples we used were vulcanizates of natural rubber (NR) and styrene-butadiene copolymer rubbers (SBR), carbon-filled and unfilled. Table 1 summarizes their preparative data. Incompressibility of these vulcanizates and some other vulcanizates were checked by dipping, stretching uniaxially, and weighing a specimen in water. 

Figure 15. The value of the pitch P as a function of temperature for LC (acetyl)ethyl cellulose/chloro-form (45 wt%, DS of ethyl groups 2.5). The filled and unfilled symbols represent the samples with acetyl DS below and over the compensation of the twist (0.19), respectively. Acetyl DS = 0.05 , 0.06 O, 0.08 A, 0.30 , 0.42 , and 0.50 (adapted from [1]).

D. Hunt, private communication concerning his measurement of total thermal contraction from 300 K to 77 K. D. Hunt made measurements on 70 different samples of various filled and unfilled plastic formulations. D. Hunt s work is unpublished. 

Unfortunately, most nondestructive evaluation techniques are not effective at finding encapsulation defects. Voids and density variations are not readily detectable by visual inspection or by x-ray analysis. In the case of x-ray, the inherently low density of encapsnlant foams limits the contrast between filled and unfilled (void) regions. Scanning aconstic microscopy (SAM) has had some limited success when the encapsulant layer is relatively thin, which is not often the case. Witness samples taken during the casting process are used to confirm foam density. 

Acetaidehyde 40 23 365 8 Resistant no or negligible changes in mass and dimensions Grilamid Emser Specimen 1 mm (0.039 in) thick samples, valid for filled and unfilled products... 

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