HER materials

Each author is responsible for mounting his/her material prior to the opening of the poster session and for removing it IMMEDIATELY after the close of the session. 

Bachelard suggests that this disposition is, for every individual, conditioned by his or her material environment ... 

In this academic work the writer might or might not use T. But if she does, the T will be a different character from the one who is teUing the reader about her childhood story. It might, for example, introduce the assignment - In this essay I will... or I interviewed... - or evaluate material - It seems to me that these two studies contradict each other. In this case the T character would represent the writer as university student writer, distanced from her material and reasonably objective. 

The second and third passages, then, are examples of how the writer seems to have found a place in her writing even when she does not appear directly in it. In other kinds of writing the writer seems to be more distanced from her material - for example, in an account of a scientific experiment or a report. Here are two examples, but remember that even these conceal the writer ... 

In summary then, in academic forms of writing it is usual for the writer to appear very little directly and, even when she uses the first person, to appear as an observer and commentator, impersonally and at a distance from her material. This may be what it looks like to an outsider. However, as we have explored, you yourself as a writer may know better. You know why you may have chosen to write about a particular topic, what your Interest is in it and... 

To develop low melting and highly processable aromatic diol extenders from resorcinol and ethylene carbonate (HER materials). 

HER materials used as chain extenders in this work were prepared based on INDSPEC Chemical Corporation s patented technology and the product details are given in Table 8.1. 

Figure 8.1 shows the viscosity-time plots of VIBRATHANE B 625 extended with HQEE and various HER materials. As can be seen, the pot life temperatures for HER materials are considerably lower than HQEE. The shorter pot life for HQEE is due to the higher processing temperature. If the processing temperature were lower than 110 °C, then HQEE would crystallise out from the solution. Premature crystallisation is a major problem encountered by most users of HQEE. But these problems are eliminated with HER-HP and other HER-TG materials due to their supercooling behaviour. 

HER Materials HQEE HER-HP HER- TG210 HER- TG225 HER- TG250 HER- TG275 HER- LIQ... 

HER Materials Analysis Hard Segment (%) Soft Segment (%)... 

Table 8.6 DSC results on cast polyurethanes from Vibrathane B 625 - HER materials ...

Figure 8.6 shows the plots of storage modulus (G ) and loss modulus (G") as a function of various technical grade HER materials along with HQEE and HER HP measured at 25 and 150 °C. The curves clearly demonstrate that G" and G" decrease as the hard segment content is decreased in these elastomers. 

Figure 8.6 Effect of HER materials on shear modulus properties...

In this work, MDI-terminated polyester prepolymer based on ethylene adipate polyol (Baytec MS-242) was used to prepare cast poly(ester urethane) materials. The HER-TG materials, HER-HP and HQEE were used as chain extenders. As discussed in section 8.4, technical grade HER materials contain various levels of high MW diols as reactive impurities. Therefore, as with poly(ether urethanes), the high MW diols are expected to play a major role in the performance of poly(ester urethanes) made with these materials. 

Pot lives exceeding 20 minutes can be easily achieved with HER materials due to their low melting and processing temperatures. Because of their supercooling behaviour and tendency to stay liquid after cooling to room temperature, further enhancement in the pot life can be achieved by lowering the mixing temperature of TG-250 and TG-275 materials. 

HER Materials HQEE HER-HP TG210 TG225 TG250 TG275... 

Figure 8.14 FT-IR stretching vibration bands of HER materials extended...

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