摘要:

AbstractThe use of coal conversion by‐products as raw materials in the synthesis of thermosetting polyesters has been investigated. Heavy tar residues were oxidized by gaseous oxygen in an alkaline medium, yielding a complex mixture of benzenecarboxylic acids and smaller amounts of aliphatic carboxylic acids. The mixture was polymerized by condensation with tetraethylene glycol “bottoms,” a by‐product of the synthesis of ethylene glycol. The resultant polyesters were cured by reacting them with epoxy resins in the presence of basic catalysts. Molded sheets and laminates were fabricated and tested. Tensile strength was found to increase with increasing curing time and with increasing concentration of epoxy crosslinking agent. Glass‐reinforced composites fabricated by the autoclave process showed an increase in flexural and shear strength with decreasing autoclave

ISSN:0021-8995    

DOI:10.1002/app.1979.070241201

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1979

数据来源: WILEY

摘要:

AbstractMechanical properties, morphology, and compatibility of polybutene‐1 blended with polypropylene, both crystallizable polymers, are described in the present study. Blends of various compositions were studied using tensile tests, differential scanning calorimetry, wide‐angle x‐ray diffractometry, and optical microscopy. A discussion on the state of compatibility and structure–property relationships for such blends in pr

ISSN:0021-8995    

DOI:10.1002/app.1979.070241202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1979

数据来源: WILEY

摘要:

AbstractEsterification of wood meal with a series of aliphatic acid anhydrides and acid chlorides in a nonaqueous cellulose solvent, an N2O4–DMF solvent, has been studied. The N2O4–DMF–pyridine solution used as the reaction medium plays a role in destroying the molecular order of the cellulose within the wood, enabling the cellulose to be uniformly substituted by acyl groups along its chain. These uniformly distributed blocking groups result in the permanent decrystallization of the wood. The acyl blocking groups are best achieved by esterification using acid chlorides in the nonaqueous solvent. Acid chlorides, from caproyl to stearoyl chloride, were found to be much more effective as acylating agents than acid anhydrides, from propionic to caproic anhydride. Although no difference in reactivity can be recognized among the acid chlorides, the reactivity decreases with increase in the number of carbon atoms in the acyl group among the acid anhyd

ISSN:0021-8995    

DOI:10.1002/app.1979.070241203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1979

数据来源: WILEY

摘要:

AbstractThe thermal softening and melting of a series of esterified wood samples, whose preparation has previously been described,4have been studied by measuring the deformation of the samples under constant load at a constant heating rate. The introduction of acyl groups into wood including part of the original crystal structure in cellulose makes the modified wood meal conspicuously thermoplastic. While untreated dry wood shows a thermal softening point (Ts) of ca. 260°C, esterified wood meal samples with acyl groups larger than caproyl have aTsof around 100°C or less, and appeared to melt over the temperature range of 220° to 250°C. In this case, the melting occurs even with wood meal samples esterified with appropriate acid chlorides in an N2O4–DMF–pyridine medium only for 30 min at room temperature. This might be the first finding that wood meal is converted, as a whole, into a thermoplastic material which can melt without any accompanying detectable degr

ISSN:0021-8995    

DOI:10.1002/app.1979.070241204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1979

数据来源: WILEY

摘要:

AbstractThe rate at which 2,3,5,6‐tetrachloro‐4‐methylsulfonylpyridine (TMP) is released from a microcapsular controlled delivery device was determined using aqueous methanol as an extraction medium. The microcapsules were prepared byin situpolymerization of a urea–formaldehyde resin. Release rate studies demonstrated that the amount of 2,3,5,6‐tetrachloro‐4‐methylsulfonylpyridine released is proportional tot−1/2and the solubility of 2,3,5,6‐tetrachloro‐4‐methylsulfonylpyridine in the extraction medium. These relationships are characteristic of a porous, monol

ISSN:0021-8995    

DOI:10.1002/app.1979.070241205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1979

数据来源: WILEY

摘要:

AbstractDynamic mechanical measurements have been made on a 4,4′‐diaminodiphenyl sulfone‐cured tetraglycidyl 4,4′‐diaminodiphenylmethane epoxy (TGDDM‐DDS). There are basically three transitions on the mechanical spectra that have been identified, and the effects of moisture uptake and amount of DDS on these transitions were examined. The dynamic mechanical behavior of the same epoxy with 60% carbon fiber loading was also studied, providing further elucidation on the nature of the transitions observed with

ISSN:0021-8995    

DOI:10.1002/app.1979.070241206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1979

数据来源: WILEY

摘要:

AbstractThe extension of the relation between the dynamic viscoelastic parameters (“E” and tan δ) and diffusion coefficient (D) to modified acrylic blend fibers indicates that the dependence of dye diffusion on polymer chain mobility is a general phenomenon not limited to a single component system. The relationship ofDto mechanical properties permits one to “tailor” fibers with good mechanical properties while maintaining adequate dye‐diffusio

ISSN:0021-8995    

DOI:10.1002/app.1979.070241207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1979

数据来源: WILEY

摘要:

AbstractPolycarbonate blends with poly(pivalolactone) were found to be completely immiscible based on the glass transitional behavior observed by thermal analysis. Crystallinity of the poly(pivalolactone) was unaffected by blending with polycarbonate. The heat of mixing of low molecular weight analogs of this system, ethyl pivalate and diphenyl carbonate, were found to be endothermic, in contrast to exothermic mixing observed for similar linear esters. Methyl branching adjacent to the ester carbonyl is believed to shield the specific interaction of this unit with the aromatic carbonate structure which leads to exothermic mixing and miscibility of similar unbranched esters with polycarbonate. Blends of poly(2,2‐dimethyl‐1,3‐propylene succinate) were found to be partially miscible with polycarbonate because the shielding is not so great since the methyl groups are further removed from the ester

ISSN:0021-8995    

DOI:10.1002/app.1979.070241208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1979

数据来源: WILEY

ISSN:0021-8995    

DOI:10.1002/app.1979.070241209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1979

数据来源: WILEY

ISSN:0021-8995    

DOI:10.1002/app.1979.070241210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1979

数据来源: WILEY