There have been a number of review papers on layered silicate and carbon nanotube reinforced polymer nanocomposites, in which the fillers have high aspect ratios. Particulate–polymer nanocomposites containing fillers with small aspect ratios are also an important class of polymer composites. However, they have been apparently overlooked. Thus, in this paper, detailed discussions on the effects of particle size, particle/matrix interface adhesion and particle loading on the stiffness, strength and toughness of such particulate–polymer composites are reviewed. To develop high performance particulate composites, it is necessary to have some basic understanding of the stiffening, strengthening and toughening mechanisms of these composites. A critical evaluation of published experimental results in comparison with theoretical models is given.

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Effects of particle size, particle/matrix interface adhesion and particle loading on mechanical properties of particulate–polymer composites

Some aspects of the surface chemistry of carbon blacks and other carbons

Thermal conductivity of carbon nanotubes and their polymer nanocomposites: A review

Dynamic covalent chemistry relates to chemical reactions carried out reversibly under conditions of equilibrium control. The reversible nature of the reactions introduces the prospects of "error checking" and "proof-reading" into synthetic processes where dynamic covalent chemistry operates. Since the formation of products occurs under thermodynamic control, product distributions depend only on the relative stabilities of the final products. In kinetically controlled reactions, however, it is the free energy differences between the transition states leading to the products that determines their relative proportions. Supramolecular chemistry has had a huge impact on synthesis at two levels: one is noncovalent synthesis, or strict self-assembly, and the other is supramolecular assistance to molecular synthesis, also referred to as self-assembly followed by covalent modification. Noncovalent synthesis has given us access to finite supermolecules and infinite supramolecular arrays. Supramolecular assistance to covalent synthesis has been exploited in the construction of more-complex systems, such as interlocked molecular compounds (for example, catenanes and rotaxanes) as well as container molecules (molecular capsules). The appealing prospect of also synthesizing these types of compounds with complex molecular architectures using reversible covalent bond forming chemistry has led to the development of dynamic covalent chemistry. Historically, dynamic covalent chemistry has played a central role in the development of conformational analysis by opening up the possibility to be able to equilibrate configurational isomers, sometimes with base (for example, esters) and sometimes with acid (for example, acetals). These stereochemical "balancing acts" revealed another major advantage that dynamic covalent chemistry offers the chemist, which is not so easily accessible in the kinetically controlled regime: the ability to re-adjust the product distribution of a reaction, even once the initial products have been formed, by changing the reaction's environment (for example, concentration, temperature, presence or absence of a template). This highly transparent, yet tremendously subtle, characteristic of dynamic covalent chemistry has led to key discoveries in polymer chemistry. In this review, some recent examples where dynamic covalent chemistry has been demonstrated are shown to emphasise the basic concepts of this area of science.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/1521-3773%2820020503%2941%3A9%3C1460%3A%3AAID-ANIE11111460%3E3.0.CO%3B2-N

Dynamic covalent chemistry.

1: Magnetic Particles: Preparation, Properties and Applications: M. Ozaki. 2: Maghemite (gamma-Fe2O3): A Versatile Magnetic Colloidal Material C.J. Serna, M.P. Morales. 3: Dynamics of Adsorption and Oxidation of Organic Molecules on Illuminated Titanium Dioxide Particles Immersed in Water M.A. Blesa, R.J. Candal, S.A. Bilmes. 4: Colloidal Aggregation in Two-Dimensions A. Moncho-Jorda, F. Martinez-Lopez, M.A. Cabrerizo-Vilchez, R. Hidalgo Alvarez, M. Quesada-PMerez. 5: Kinetics of Particle and Protein Adsorption Z. Adamczyk.

Surface and Colloid Science

Resveratrol-based tri-functional benzoxazines: Synthesis, characterization, polymerization, and thermal and flame retardant properties

The influence of a hexagonal boron nitride powder surface on the polymer- ization of a benzoxazine monomer is examined by differential scanning calorimetry (DSC). By varying the thickness of the benzoxazine coatings on boron nitride particles, a distinct influence of the surface substrate on the polymerization reaction could be observed. At a coating thickness calculated to be on the order of a monolayer, the heat of reaction is reduced, while the exothermic peak temperature and peak width at half height are increased relative to that of the neat resin values. The reduced heat of reaction and increased exothermic peak temperature indicate that the boron nitride surface is inhibiting the benzoxazine polymerization reaction. In the intermediate coating thickness region, the heat of reaction increases and the exothermic peak temperature and peak width at half height decrease with increasing coating thickness. With even thicker coatings, the heat of reaction and exothermic peak temperature and peak width at half height reach values corresponding to that of the neat resin and no longer change with thickness. In addition, the influence of surface treated boron nitride particles on the thermal polymerization behavior, as well as the effect of the surface treatment on the viscosity, dynamic mechanical properties, and flexural properties of the filled composites are also investigated. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2360 -2372, 1999

Investigation of the boron nitride/polybenzoxazine interphase

FT-IR spectroscopy was used to collect spectra of γ-aminopropyltriethoxy silane (γ-APS) coupling agent deposited on KBr plates, modeling the silane interphase of composites, to study the effects of heating the γ-APS film under various environmental conditions. This coupling agent is used in fiber-reinforced epoxy composites. An aminebicarbonate salt forms when the sample is dried in a moist carbon dioxide environment giving rise to a series of bands from 2800 to 2000 centimeter−1 (cm−1) and bands at 1637 cm−1, 1330 cm−1, 696 cm−1, and 663 cm−1. The primary amine group is split into two bands at 1572 cm−1 and 1486 cm−1 in the NH3+ form. Heating removes the aminebicarbonate salt at temperatures above 95°C and condenses the γ-APS polymer to a polysilsesquioxane film. The aminebicarbonate salt partially reforms if the γ-APS film is stored in a moist CO2 environment. At temperatures above 120°C the primary amine of γ-APS is oxidized in air to imine groups. In the process of evolving the CO2 the polymer is further condensed and the amine groups can be converted to imines if the temperatures exceeds 120°C. Both processes reduce the reactivity of the coupling agent with the epoxy resin. The structure of the silane interphase must be controlled during the processing of the composite to yield materials with maximum properties.

The Silane Interphase of Composites: Effects of Process Conditions on Gamma-Aminopropyltriethoxysilane

A main-chain-type polybenzoxazine with amic acid and benzoxazine groups as repeating units, generally termed as poly(benzoxazine amic acid) (poly(BZaa)), has been synthesized. Different from traditional main-chain polybenzoxazines, poly(BZaa) can undergo polymerization and imidization reactions to form cross-linked polyimide (cPI) after certain thermal treatment. cPI can further undergo a typical cyclization to give cross-linked polybenzoxazole (cPBO) after an additional thermal treatment. A model reaction is designed based on the reaction of 3-phenyl-2,4-dihydro-2H-benzo[e][1,3]oxazin-9-amine with a phthalic anhydride. Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopies are used to confirm the structure of model compound. The ring-opening polymerization behavior of benzoxazine monomers and main-chain polybenzoxazine is studied by differential scanning calorimetry (DSC). Thermal properties of the cross-linked polymers are also studied by dynamic mechanical analy...

An Ultrahigh Performance Cross-Linked Polybenzoxazole via Thermal Conversion from Poly(benzoxazine amic acid) Based on Smart o-Benzoxazine Chemistry

Continuous fiber, high-performance composites have found increased use in the design of a large number of civilian and military aircraft. However, the brittle nature of the carbon fiber and the resins used as matrices have restricted the full utilization of these materials in aerospace application. Hence, the development of toughened composites has a great potential for expanding the use of current materials, and a major effort is being undertaken in order to develop toughened composites. Due to several advantages of introducing a ductile or flexible material between the fiber and matrix, coating the fiber with polymers has recently received considerable interest and much effort has been done to understand the effect of the interlayer on composite properties. This paper reviews the technology of toughening composites by fiber coating, showing the composite systems, coating materials, fiber coating methods and toughness mechanisms which have been studied. Finally, a separate section is dedicated to reviewi...

Hatsuo Ishida

Papers

Resveratrol-based tri-functional benzoxazines: Synthesis, characterization, polymerization, and thermal and flame retardant properties

Investigation of the boron nitride/polybenzoxazine interphase

The Silane Interphase of Composites: Effects of Process Conditions on Gamma-Aminopropyltriethoxysilane

An Ultrahigh Performance Cross-Linked Polybenzoxazole via Thermal Conversion from Poly(benzoxazine amic acid) Based on Smart o-Benzoxazine Chemistry

Toughening composites by fiber coating: a review