THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The Design and Analysis of Experiments

Structural engineering of polyurethane coatings for high performance applications

The structural and mechanical properties of gels formed from biopolymers are discussed both in terms of the techniques used to characterise these systems, and in terms of the systems themselves The techniques included are spectroscopic, chiroptical and scattering methods, optical and electron microscopy, thermodynamic and kinetic methods and rheological characterisation The systems considered are presented in order of increasing complexity of secondary, tertiary and quaternary structure, starting with gels which arise from essentially ‘disordered’ biopolymers via formation of ‘quasicrystalline’ junction zones (eg gelatin, carrageenans, agarose, alginates etc), and extending to networks derived from globular and rod-like species (fibrin, globular proteins, caseins, myosin) by a variety of crosslinking mechanisms Throughout the text, efforts are made to pursue the link (both from experiment and from theory) between the structural methods and mechanical measurements As far as we are aware this is the first major Review of this area since that of J D Ferry in 1948 — The interest shown by polymer physicists in more complex biochemical systems, and the multi-disciplinary approaches now being applied in this area, make the format adopted here, in our opinion, the most logical and appropriate

Structural and mechanical properties of biopolymer gels

Engineering applications of synthetic polymers are widespread due to their availability, processability, low density, and diversity of mechanical properties (Figure 1a). Despite their ubiquitous nature, modern polymers are evolving into multifunctional systems with highly sophisticated behavior. These emergent functions are commonly described as “smart” characteristics whereby “intelligence” is rooted in a specific response elicited from a particular stimulus. Materials that exhibit stimuli-responsive functions thus achieve a desired output (O, the response) upon being subjected to a specific input (I, the stimulus). Given that mechanical loading is inevitable, coupled with the wide range of mechanical properties for synthetic polymers, it is not surprising that mechanoresponsive polymers are an especially attractive class of smart materials. To design materials with stimuli-responsive functions, it is helpful to consider the I-O relationship as an energy transduction process. Achieving the desired I-O linkage thus becomes a problem in finding how to transform energy from the stimulus into energy that executes the desired response. The underlying mechanism that forms this I-O coupling need not be a direct, one-step transduction event; rather, the overall process may proceed through a sequence of energy transduction steps. In this regard, the network of energy transduction pathways is a useful roadmap for designing stimuli-responsive materials (Figure 1b). It is the purpose of this review to broadly survey the mechanical to chemical * To whom correspondence should be addressed. Phone: 217-244-4024. Fax: 217-244-8024. E-mail: jsmoore@illinois.edu. † Department of Chemistry and Beckman Institute. ‡ Department of Materials Science and Engineering and Beckman Institute. § Department of Aerospace Engineering and Beckman Institute. Chem. Rev. XXXX, xxx, 000–000 A

Mechanically-induced chemical changes in polymeric materials

Isocyanate, and Non-isocyanate Polyurethane Etienne Delebecq,† Jean-Pierre Pascault,‡,§ Bernard Boutevin,† and Franco̧is Ganachaud*,†,‡,§ †Institut Charles Gerhardt, UMR 5253 CNRS, Ingeńierie et Architectures Macromolećulaires, Ecole Nationale Supeŕieure de Chimie de Montpellier, 8 rue de l’ećole normale, 34296 Montpellier, Cedex 05, France ‡INSA-Lyon, IMP, UMR5223, F-69621, Villeurbanne, France Universite ́ de Lyon, F-69622, Lyon, France

On the Versatility of Urethane/Urea Bonds: Reversibility, Blocked Isocyanate, and Non-isocyanate Polyurethane

A synchrotron X-ray study of melting and recrystallization in isotactic polypropylene

The sol−gel transition, or gelation, in a polymer network-forming system is defined as the critical point in the polymerization at which an infinite macromolecule is formed. There are many studies in the literature concerning the exact and accurate determination of the gel point and its interpretation in terms of the critical conversions of reactant functional groups. However, these have mainly involved step-growth polymerizations with few studies of chain-growth polymerizations such as that described in this study. Chemorheological studies on a cationically polymerized epoxy network-forming system are used to determine accurate gel times and critical conversions, which are interpreted in terms of classical branching and chemical bond percolation models for nonlinear polymerizations. Rheological studies during the polymerization of a trifunctional epoxide monomer, using BF3 as the Lewis acid initiator, yielded a gel conversion of 0.17 ± 0.02 and a power law dependence for the development of shear modulus,...

Rheological Behavior and Gel-Point Determination for a Model Lewis Acid-Initiated Chain Growth Epoxy Resin

https://www.research.manchester.ac.uk/portal/files/60011273/PA6_PLSN_Tensile_Accepted.pdf

Tensile properties of melt intercalated polyamide 6 / Montmorillonite nanocomposites

Polymer-layered silicate nanocomposites (PLSN), based on polyamide 6 (PA6) and montmorillonite (MMT) modified with an octadecylammonium salt, were produced via melt compounding in a co-rotating twin-screw extruder. Wide angle X-ray diffraction (WAXD) and TEM revealed a PLSN containing 3.3% by weight (wt.-%) of MMT to exhibit a mixed exfoliated/intercalated morphology, consisting mainly of individual silicate lamellae together with some intercalated stacks, resulting in a mean value of 1.8 lamellae per particle. In contrast, a PLSN containing a higher level of 7.2 wt.-% MMT exhibited a more ordered intercalated structure, consisting mainly of a distribution of lamellae stacks with a mean value of 3.8 lamellae per particle. The dispersion of MMT in the PLSN generated very large polymer-filler interfacial areas, resulting in significant increase in the volume of constrained PA6 chain segments. Consequently, significant changes in the ratio of α/γ crystallites and in the thermal behaviour of the matrix PA6 were observed during WAXD, DSC and dynamic-mechanical thermal analysis (DMTA) studies of the PLSN. In particular, damping data from DMTA showed relaxations between T g and T m resulting from amorphous polymer chain segments constrained at the polymer-filler interface, indicating the formation of a continuous phase of constrained polymer. In contrast, a PA6 microcomposite formed using unmodified MMT generated much lower polymer-filler interfacial area, with most of the MMT residing within large, poorly wetted aggregates. Consequently, changes to the thermal behaviour of the matrix PA6 were much less significant than those induced in the PLSN.

Structure and Dynamic Mechanical Properties of Melt Intercalated Polyamide 6—Montmorillonite Nanocomposites

Furan-based diisocyanates and diamines were prepared unambiguously as potential monomers for polyurethane and polyamide production, starting from methyl furoate and furfurylamine, respectively. The syntheses were optimized and the product identity was confirmed by elemental analysis, IR and NMR spectroscopy, and also by preparation of derivatives which were similarly characterized.

John L. Stanford

Papers

A synchrotron X-ray study of melting and recrystallization in isotactic polypropylene

Rheological Behavior and Gel-Point Determination for a Model Lewis Acid-Initiated Chain Growth Epoxy Resin

Tensile properties of melt intercalated polyamide 6 / Montmorillonite nanocomposites

Structure and Dynamic Mechanical Properties of Melt Intercalated Polyamide 6—Montmorillonite Nanocomposites

Polymers from renewable sources, 1. Diamines and diisocyanates containing difurylalkane moieties