ABSTRACT： This is a study of the flow properties of a range of magnetic toners produced from a common base in relation to three physical variables – the milling method, the type and amount of flow additive and to a limited extent, particle size. Two methods of milling were used for sample preparation – air jet milling and mechanical milling. The flow additives were either HMDS or PDMS silicas. The study used the FT3 powder Rheometer (Freeman Technology) to determine the rheology of powder samples in terms of the energy required to cause a powder to flow. The dependence upon environmental factors commonly imposed on powders such as flow rate, the level of aeration and the amount of consolidation are determined for each of the materials. The propensity to retain air is also investigated and quantified. The results clearly indicate the complex nature of toners and how their flow properties are affected by a large number of variables, of which one of the most significant is the effect of aeration and de-aeration representing the transition from fluidisation to consolidation.

ABSTRACT: When an alternating stack of molten polymer sheets is pulled in uniaxial tension parallel to the layers, interfacial area per unit volume increases, amplifying interfacial effects. Multilayers of several polymer pairs were prepared by lamination ( up to 100 layers). Pairs with low and high interfacial tension, G, and pairs with functional groups which could react were selected. These were stretched at 220°C at various constant extension rates in a rotating clamp extensional theometer. At low rates the extra measured stress could be related to G and the number of interfaces. At higher extension rates extra stress exceeded G. This method for measuring interfacial tension can be applied to opaque samples and does not knowing sample density or viscosity. For the reactive pairs there was pronounced strain hardening caused by coupled and even cross linked chains at each interface. The contribution of the cross linked interface was shown to follow rubber elasticity theory. As a result of the reaction the measured stress was two orders of magnitude higher than for the nonreactive case. Extra stress due to the grafting reaction was also measured. It increased with extension rate, presumably due to entanglements of the grafts across the interface.

ABSTRACT: The relationship of extrudate swell occurring in capillary rheometer and extruder is the aim of this study. Three assumptions used are: (1) the molten polymer is sheared and given the largest deformation at the entrance of the die; (2) the retraction of an elastic part occurs during the molten flow in the die, and (3) the total retraction of the melt appears at the exit of the die. The largest deformation at the entrance of the die depends linearly onshear rate and the retraction in the die depends linearly on both shear rate and die dimensions (diameter and length), which is defined as a retraction function. Separation of these two effects on the largest deformation and the retraction function is proposed by defining a ‘extrudate swell rate function, K’ as (r()2-1)/w’ where  is the extrudate swell ratio and  is the shear rate. This indicates that K is a function of shear rate, die dimension and melt properties, similar to the retraction function. Extrudate swell of natural rubber compounds mixed with carbon black and calcium carbonate were examined with a capillary rheometer and an extruder at processing temperature of 100°C. The die used had various sizes varying from 1.5mm – 5.5 mm in diameter and 16mm – 30mm in length while shear rate is varied from 1 2000s-1. The results show that the empirical extrudate swell rate function K is equal to Anwwhere n is a constant varying from –0.70 to –0.89 depending on the type of compounds and A is a constant varying from 0.5 to 0.8 depending on the die length. An agreement between the extrudate swell rate functions (K) obtained either from the capillary rheometer and or with the extruder is discovered. Therefore, extrudate swell behaviour observed in laboratory equipment as a capillary rheometer can be used to explain the behaviour in an industrial extruder.

An experimental study was carried out to study andcharacterize the capillary e.xtrudate swell and parisonswell behal-ior in extrusion blow molding of two commer-cial blow molding grade high density polyethylene resins.The capiIIa~ extrudate swell behavior of these resins weredetermined employing a capillary rheometer and a specialthermostatting chamber. Parison swell behavior was de-termined using an Impco Al3-R12 reciprocating screwblow molding machine in conjunction with cinematogra-phy and pinch-off. The experimental conditions underwhich capiiiaq extrudate and parison swell data can berelated are elucidated. Excellent agreement is found be-tween the area swell values determined on the basis ofcapillary and parison swell experiments.

ABSTRACT: Tensile stress and birefringence in both real and model amorphous polymer melts have been measured during constant rate uniaxial elongational flow. We focus on investigations where deviations from the linear stress-optical behavior are pronounced. A rate-dependent contribution to the stress which is not directly related to the intramolecular conformations (“stress offset”) is detected for both types of macromolecular fluids. Independent of the flow history, during relaxation a linear stress-optical behavior is revealed. Nonequilibrium molecular dynamics (NEMD) computer simulations on the multibead anharmonic spring model are shown to provide insight into the molecular mechanisms underlying the viscoelastic behavior: during relaxation the intermolecular interactions become dominant in correlation with linear stress-optical behavior; the stress offset shown to be very similar to the stress arising in the corresponding simple fluid; the total stress can well be approximated by a sum of three parts which are based on single-particle and single-link distribution functions only; the yield point behavior at high elongation rates reflects the transition from affine to nonaffine motion of bonds and is understood without reference to strong inhomogeneities resulting from local plastic strain production[the chemical structure does not influence the qualitative behavior]; distinct microscopic stress contributions under elongation and subsequent relaxation such as inter- and intramolecular, attractive and repulsive, kinetic and potential contributions are resolved.

Abstract： This paper concentrates on the principles and measurement of interfacial tension and its value in predicting the contamination of oil e.g. by organic polar compounds which are formed by the interaction of oil, water and oxygen and reduce the functionality of the oil. These contaminants are attracted to the oil/water interface and as a result significantly lower the interfacial tension. A pure interface is compared to one modified by surface active additives for the effect on interfacial tension, various methods for measuring interfacial tension are described and a method using interfacial tension to determine the polar and dispersed components of a liquid will be explained.. The ASTM Standard D971 will be discussed and results shown for both transformer and lubrication oils. The question ‘The Surface Tension Test - Is it Worth resurrecting?’1 can be discussed during Question Time.

There have been quite a few types of equation of state and abundant pi-a curves of various lipid monolayers at the air-water or the oil-water interface in the literature. However, it has been a problem to interpret mechanochemical properties of bilayer vesicles from the pi-a information of the monolayer. In fact, even the bilayer surface pressure has not yet been well characterised although the monolayer surface pressure has already been traditionally defined as the lowering in the surface tension from the clean interfacial tension due to the presence of the monolayer. The monolayer-bilayer correspondence problem therefore could not be well defined and completely solved in spite of its importance in practice to apply the monolayer pi-a data to elucidate bilayer vesicle properties and to theoretically study biomembranes. In the present analysis, we thus firstly define the bilayer leaflet pressure as the intrinsic pressure of the lipid layer system, which is the sum of the net repulsive interaction of the lipids within the lipid layer and the hydrophilic interaction of the headgroups.

By using a composite subphase, the atypical amphiphilic rare earth complex REL3Phen molecules (figure 1) without long hydrophobic chains were fabricated into LB films, where RE denotes Eu(III), Sm(III) and Tb(III); L denotes b-diketone ligands acac (acetylacetone), TFA(trifluoroacetylacetone), HFA(Hexafluoro- acetylacetone) and TTA(thenoyltrifluoroacetone); and Phen denotes 1,10-phenanthroline. Excited by ultraviolet irradiation, the LB film containing the Eu(III) or Sm(III) complex can emit strong red fluorescence, and the LB film containing the Tb(III) complex can emit strong green fluorescence. The fluorescence signal can be detected from a single layer.

通常我们用一台材料试验机进行多种测试。在各种测试中所需的载荷范围不同。如果所用的载荷传感器测试范围窄，我们就需不断更换不同的载荷传感器来满足不同的测试工作。 我们常用的载荷传感器的测试范围一般为从载荷传感器的满量程到期满量程的1/50。 现以5kN（500kg）的材料试验机在塑料领域测试为例：在5kN(500kg) 到100N (10kg)的范围内满足0.5%的精度要求。 该范围可进行大部分硬塑料的测试要求。而对橡塑材料的测试往往会在10kg以下，则不能满足0.5%的精度要求，即在10kg一下必须使用其他载荷传感器。 在实际测试中要不断更换载荷传感器进行不同的测试。 然而，如果我们采用超大测试范围的载荷传感器时，即测试范围可达1/1000，一个传感器既可覆盖整个测试范围，5kN-5N (500kg-0.5kg)（如下图所示）。这样可使我们的日常操作简单得多。

ABSTRACT:We investigate therheological behavior of Langmuir monolayers consisting of polyisoprene chains tethered by one end to the air/water interface. These 10-50 nm thick monolayers provide model systems of a molten polymer brush for which the ends can move within the interface. Their linear viscoelastic properties are determined by applying a small-amplitude shear flow within the interface plane and investigated as a function of surface density and length of tethered chains. When increasing the chain length, we observe a transition from a liquidlike to at ransient network behavior typical of entangled bulk polymer melts. The terminal relaxation time and the effective bulk zero shear viscosity of themonolayers are 2-3 orders of magnitude higher than those of a linear bulk polyisoprene melt of identical molecular weight. Both quantities are shown to exhibit an enhanced molecular weight dependence and to increase with surface density.

ABSTRACT:Lipopolymers are known to for matwo-dimensional physical network (physicalgel)at the air－water interface that is stabilized by two different types of associative interactions : microcondensation of alkyl chains of lipopolymers to form small clusters and physical junction zones linking neighboring polymer chains stabilized by hydrogen bonding of water molecules. In this study we present surface rheology and film balance experiments on amphiphilic PEG lipopolymers of different molecular weights of their polymer moiety(MW:750,1000,2000,3000,5000)at the air-water interface. Our experimental data show that the gelation transition shifts within the MW range of 1000-5000 to smaller areas per molecule as the polymer chain length gets shorter until it reaches a specific minimum area where no further change is observed(MW ＝1000). Surface rheology data of the storage modulus indicate a qualitative difference between higher MW species (MW:2000,3000,5000)and lower MW species (MW:750,1000).While the well-known power law dependence above the gelation point can be observed in the first case, a breakdown of the network after an initial power law-like behavior is found in the latter one. Our data suggest that a sufficient area mismatch between polymer and lipid moieties of these peculiar amphiphiles is essential for a stable two-dimensional physical network to form.