Data for composites

A comparison of Horton s data for composite propellants with the theoretical results of Hart and Friedly is difficult. The theoretical studies are based on premixed flames, which are more appropriate for double-base propellants. The applicability of premixed flames to composite propellants is open to question, as indicated in Section II. Brown et al. (B13) have indicated that the data are consistent with the expected contributions of surface reactions in the transient combustion process. These comparisons are preliminary, however, and more research is required to study these observations in detail. 

C. Each Figure shows titration data for compositions inside of the miscibility gap (where the "curve" is linear), as well as enthalpies in a single-phase region. Data from the literature are also shown for comparison with the present results (13-161. Table I shows values of the compositions of the aqueous and amphiphilic phases for n-butanol/water at 30.0 and 55.0 °C and for n-butoxyethanol/water at... 

Four nitrosamines, seven nitramines, three nitroesters and the explosives Semtex 10 and Composition B have been investigated by TGA. Linear dependence was confirmed between the position of the TGA onsets, as defined in the sense of Perkin-Elmer s TGA-7 standard program, and the samples weights. The slope of this dependence is closely related to the thermal reactivity and molecular structure. The intercept values of the dependence correlate with the autoignition temperatures and with the critical temperatures of the studied compounds, without any clear influence from molecular structure. Results show that Semtex 10 exhibits approximately the same thermostability as its active component pentaerythrityl tetranitrate (PETN, 274). Results also show that TGA data for Composition B do not correlate with analogous data for pure nitramines564. 

Generally, the extra grades will have more benzyl acetate and p-cresyl methyl ether, a high proportion of linalool and a lower proportion of sesquiterpenes when compared to lower grades. The lower grades have increased sesquiterpenes, with a resultant harsher oily character. Table 7.5 shows typical published data for compositions of the various grades. 

Although the numerical evaluation shows the possible thermoelectric property enhancement, there are not any appropriate experimental data on thermoelectric properties of composite. The aim of the following experimental procedure and some results is to collect basic data for composite thermoelectric materials design. 

Naim [178] performed linear elastic stress analysis of residual stresses in unidirectional high-performance composites containing high-modulus fibers and an interphase region. Naim and Zoller [179] provided data for composites with thermoset and thermoplastic matrices, and showed by linear elastic stress analysis how the buildup of residual thermal stresses during fabrication is related to the disparate thermal expansion properties of the fibers and matrices. 

Table VI. Summary of Specific Heat Data for Composite Materials ...

An eqnation has been derived relating the effective diffusivity of porous foodstuffs to various physical properties such as molecular weight, bulk density, vapor space permeability, water activity as a function of material moisture content, water vapor pressure, thermal conductivity, heat of sorption, and tanperature [80]. A predictive model has been proposed to obtain effective diffusivities in cellular foods. The method requires data for composition, binary molecular diffusivities, densities, membrane and cell wall permeabilities, molecular weights, and water viscosity and molar volume [81]. The effect of moisture upon the effective diffusivity is taken into account via the binding energy of sorption in an equation suggested in Ref. [77]. 

Data for composites containing HAR-160 mica is shown in Table 14.26. In composites containing untreated mica, annealed specimens with HAR-160 mica had flexural modulus increases of 27.0%, 20.8%, and 15.7% for 20, 30, and 40 wt% loadings, respectively, when compared with unannealed specimens. The largest increases were obtained with the lowest amount of mica because there are more... 

All the advantages and disadvantages of the discussed procedures are summarized in Table 1. Since reliable data for composites do not exist up to now, the assessment of the different procedures is mainly based on data on joining of thermoplastics without reinforcing structures. This was extended by our preliminary results achieved on reinforced thermoplastics. 

Chapters 3-5 address the mechanisms associated with fluid ingress and polymer molecular structure, simple ways in the laboratory to obtain phenomenological data for composites prepared using a given manufacturing process (for example using pre-preg s cured in an autoclave oven or recently popular VARTM based approach)... 

Figure 11.5 SAXS-determined morphology data for compositional fractions of ethylene-octene copolymers number-averaged lamellar thickness (open squares), crystal core thickness (open circles), transition layer thickness (stars). Reprinted with permission from Reference [28]. Copyright 1993 American Chemical Society.

---