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Coefficients of thermal linear and volumetric expansion (CTE, CVE) of crystal lattice for 13 fully aromatic crystalline polyimides (PIs) were evaluated from lattice parameters measured from variable-temperature (VT) synchrotron X-ray diffraction patterns, and the effects of chemical structure on CTE and CVE are discussed. The smallest CVE (116 ppm K–1) was observed for PMDA-PPD with the simplest rigid-rod structure, and the largest CTE anisotropy was observed for PMDA-ODA containing an ether linkage with an extraordinarily negative CTE a (−44 ppm K–1). The values and anisotropy of the CTEs strongly depended on the crystalline structure, whereas the CVEs were negatively correlated with the weight density, regardless of the PI type. The correlation was explained using the Grüneisen equation, (∂V/∂T) P /V = γC v,interχ, assuming that isothermal compressibility χ dominates the equation. An increase in the weight density and/or molecular weight of repeating units effectively suppresses the CVEs of crystalline PIs.

The relationships between the molecular structure, polymer chain orientation, β‐transition temperature, and the coefficients of in‐plane and out‐of‐plane linear thermal expansions (CTE, α), as well as the coefficients of volumetric thermal expansion (CVE, β), are extensively examined for ten types of self‐standing aromatic polyimide (PI) films via thermomechanical analysis, near‐infrared optical interferometry, and dynamic mechanical analysis. The out‐of‐plane CTEs (α⊥) of PI films having rigid‐rod structures are 20–40 times larger than their in‐plane CTEs (α//), whereas the α⊥ values of PI films having bent linkages in the main chains are comparable to their α// values. In addition, the values of normalized anisotropy in CTE for PIs (η), defined as (α⊥ −α//)/β, are proportional to the orientation coefficients (P200) estimated from the in‐plane/out‐of‐plane birefringence (Δn) and molecular polarizability tensor. Furthermore, larger CVE values are observed for PIs exhibiting lower β‐relaxation temperatures (Tβ), at which localized molecular motion occurs. In contrast, smaller CVE values are observed for PIs exhibiting higher Tβs because their local molecular motions are suppressed due to the structural rigidity and dense molecular packing.

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The infrared absorption spectra of selected crystalline and noncrystalline bands were studied in bulk‐crystallized specimens of linear polyethylene which encompassed the extremely wide density range of 0.92–0.99 g./cm.3. The analysis of the data obtained at room temperature yield degrees of crystallinity by infrared methods which are in very good accord with the values deduced from the density measurements. Studies of the infrared spectra as a function of temperature give fusion curves which are in agreement with those obtained by thermodynamic methods. However, in order to obtain these latter results cognizance must be taken of the large negative temperature coefficient of the specific extinction coefficients of the crystalline bands from room temperature to the melting point. The necessary data to account for this phenomena were obtained from studies of the spectra of the n‐paraffin, C94H190, where molecular crystals are formed. Analysis of the two gauche bands, at 1352 and 1303 cm.−1, which are assigned to the noncrystalline regions demonstrate that for bulk‐crystallized samples of lowest densities the intensity ratio at room temperature is identical to that expected from the pure melt at this temperature. The conclusion is thus reached that the noncrystalline regions in these cases and the pure melt are structurally very similar. For samples of higher density, where the crystallite size is comparable to the extended chain length, the intensity ratio of the two gauche bands is altered. This change could reflect a change in the sequential distribution of gauche bonds. This intensity ratio for crystals formed from dilute solution is very similar to that for the high‐density bulk‐crystallized material and indicates a similarity in structure of the noncrystalline regions in the two cases.

A facile and non-distractive method for estimating thermal emissivity of solid polymers based on ATR-FT-IR method was newly developed. This method is applicable to thick and nontransparent samples without using blackbody furnace. The thermal emissivity estimated by this method is consistent with the reference values obtained using blackbody furnace. The ATR-IR method enables to estimate thermal emissivity of polymer materials having arbitrary shapes not only bulk and films but also forms and fabrics.

Tilting of the crystal profile during directional solidification is studied numerically, when the crystalline axis is misoriented from the temperature gradient and the pulling direction. Only with the anisotropy in surface stiffness is the crystal shown to tilt to an angle smaller than the misorientation of the crystalline axis . The angle approaches on increasing the pulling velocity V, as is often observed in experiments. The V dependence of the tilting thus does not necessarily mean that the tilting is caused by the kinetic effect. With ϭ45°we observe tip splitting and double fingers, a constituent of the compact seaweed pattern. ͓S1063-651X͑96͒05907-7͔

Recently, it has been reported that morphine, a representative m-opioid receptor (MOR) agonist, showed an analgesic activity in the periphery in mice.1) Additionally it has been recognized that tolerance to the peripheral analgesia was not developed after the repeated administration of morphine in mice.2) Furthermore, it has been reported that the MORs were increased around the inflammatory tissues in animals and humans.3,4) These reports indicate that the MOR agonists are useful analgesics in the periphery, especially against the inflammatory tissues.On the other hand, there are nonsteroidal antiinflammatory drugs (NSAIDs) as peripheral analgesics but they do not have an analgesic efficacy toward some serious peripheral inflammations.5) Therefore, we think that in the serious inflammation cases such as severe burns and grazes, MOR agonists can be effective medicines.As MOR agonists not having the morphinane structures, fentanyl, 6) loperamide 7) and diphenoxylate 8,9) are known. As for fentanyl, to improve the quality of life for cancer patients with pain, the plaster, 10) which has an analgesic activity that lasts for far seventy-two hours, has been developed so the patients do not need to go frequently to the hospital. Although loperamide and diphenoxylate are MOR agonists, they do not easily pass through the blood-brain barrier (BBB). Therefore, they are mainly used as antidiarrheals now.Recently, it has also been reported that when loperamide was administered to a burn on a rat as a peripheral percutaneous cream, it was effective and could not easily pass through the BBB so the manifestation of tolerance did not occur. 11)Therefore, our final objective is the synthesis of MOR agonists having peripheral analgesic activity, and as the first step, we intended to synthesize compounds having more potent activities than loperamide in the two in vitro tests mentioned in the above summary. The three compounds mentioned above have a piperidine moiety in their structures. Currently there is no compound having a piperazine moiety in the structure as a MOR agonist on the market. Therefore, we started to synthesize compounds having a piperazine moiety in their structures. In this paper, we describe the synthesis of the compounds and their affinities to the human MOR and dand k-opioid receptors (DOR and KOR) expressed in CHO cells and their agonist activities on MOR in guinea-pig ileum. ChemistryTo develop our new MOR agonists instead of the already known MOR agonists not having morphinane structures, we thought that our compounds had to have a structural feature. Therefore, based on the knowledge already known, we designed the piperazine (nϭ1) or homopiperazine (nϭ2) derivatives, which have side chains of fentanyl, diphenoxylate and loperamide on a nitrogen with another nitrogen directly connected to various aromatic rings including the heteroaromatic rings.Considering the novelty of our compounds, we first selected the heteroaryl groups as aryl groups. It has been well known that a halogen located in the a-or g-positio...