Abstract--Thirty two boehmites, synthesized at temperatures ranging from room temperature to 300~ were examined by scanning electron microscopy, transmission electron microscopy, electron diffraction, X-ray powder diffraction, differential thermal analysis, and infrared spectroscopy. The results show that boehmite exhibits a continuous gradation in crystallite size ranging from single octahedral layers or a few unit cells to about 65 unit cells in the y-direction. This conclusion suggests that the term pseudoboehmite is inappropriate for finely crystalline boehmite. Finely crystalline boehmite contains more sorbed water than coarsely crystalline boehmite; this water is commonly intercalated between octahedral layers, usually randomly but sometimes regularly. The regularly interstratified boehmite gives rise to a diffuse "long spacing" X-ray diffraction reflection. Calculated 020 X-ray diffraction peaks approximate closely those observed experimentally when a range of crystallite sizes is taken into account.

Abstract--The crystal structure of a synthetic boehmite sample has been refined to an R of 0.047 in the space group Amam from X-ray powder diffraction data. Inclusion of hydrogen atoms and/or refinement in the space group A21am gave poorer results. Cell dimensions were determined as a = 3.6936 (_+ 0.0003), b = 12.214 (-+ 0.001), c = 2.8679 (_+ 0.0003) ~,. All AI-O(OH) distances lie between 1.88 and 1.91/~. Shared octahedral edges are 2.51-2.52/~, and unshared octahedral edges are 2.86-2.87/~, in excellent agreement with those for layered silicates. The O-H... O distance between contiguous octahedral sheets is 2.71/~. The computed X-ray pattern matches closely with the experimental pattern, indicating the degree to which the crystal structure has been determined.

The practical strength of glass is highly dependent on the amount and type of damage that a glass article has experienced in its lifetime and can be 50% less than its theoretical strength. Glass reinforcement fibers in the pristine state exhibit some of the highest failure strengths of any glass form. Strength degradation is a sequential process the further from the point of formation a glass travels. Individual filament strength is important in the manufacturing process as the fiber interacts with water, HVAC, sizing applicators, contact shoes, and guide eyes and ultimately this combination impacts productivity. A discussion of glass fiber strength — pristine versus usable, and the effects of temperature, humidity, and composition on glass strength follows in this manuscript. New data collected in Owens Corning's Glass Properties Laboratory on the effect of temperature and relative humidity on strength and modulus for Advantex® glass, Owens Corning's S‐glass (XStrand®S, FliteStrand®S, and ShieldStrand®S) and H‐glass (WindStrand®H) are presented. Owens Corning's understanding of the effect of composition on strength and modulus, and particularly how individual oxides contribute to these properties are shared.