Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1572-8935
    Keywords: Thermotropic ; Thermally stimulated current ; Co[poly(ethylene terephthalate-p-oxy-benzoate)]
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A series of co[poly(ethylene terephthalate-p-oxybenzoate)] thermotropic copolyester with different compositions were prepared by the copolymerization of either poly(ethylene terephthalate) (PET) polymer or its oligomer with p-acetoxybenzoic acid. Thermally stimulated current (t.s.c.) method can be employed to evaluate the characterization of this type of liquid crystalline polymers (LCPs). The transition/relaxation of liquid crystalline polymers around its glass transition temperature have been investigated. When an electric field is applied for a period of time, it results in annealing of this copolymer. The t.s.c. method which seems particularly important to the complex multiphase structure of the liquid crystalline polymers can provide good information about the randomness of two moieties in the backbone of this copolymer.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 47 (1993), S. 1105-1113 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A series of co[poly(ethylene terephthalate-p-oxybenzoate)] thermotropic copolyester with different compositions were prepared by the copolymerization of either poly(ethylene terephthalate) (PET) polymer or its oligomer with p-acetoxy-benzoic acid. The polymeric products were subjected to solid-state polymerization for various time intervals. Effects of composition ratio and solid-state polymerization time on X-ray diffraction behavior were investigated. It is found that the effect of transesterification induced by solid-state polymerization causes an increase in crystallinity with the copolyesters having high mol % of p-oxybenzoic acid (POB) moiety and causes a decrease in crystallinity with the copolyesters having high mol % of PET moiety. In general, the crystallinity of copolyesters is first increased and then decreased as solid-state polymerization time proceeds. However, the crystallinity of copolyester having POB/PET = 80/20 composition is increased generally at 4-h solid-state polymerization. It is also found that the crystallinity of copolyesters is decreased by quenching. The copolyester based upon either PET oligomer with 4-h solid-state polymerization or PET polymer with 8-h solid-state polymerization shows the most similar X-ray diffraction pattern with that of Eastman 10109. © 1993 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 51 (1994), S. 1727-1734 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A series of co[poly(ethylene terephthalate-p-oxybenzoate)] thermotropic copolyesters with various compositions were prepared by the copolymerization of either poly(ethylene terephthalate) polymer (PET) or its oligomer (OET) as moiety (II) and p-acetoxy-benzoic acid (POB) as moiety (I). The polymeric products obtained were then subjected to solid-state polymerization. The glass and melting transitions of the copolyesters obtained have been studied by differential scanning calorimetry (DSC). Effects of composition and solid-state polymerization on DSC are discussed. The melting point of copolyesters possesses a higher value if the PET polymer is used as PET moiety in the copolyesters. In the DSC scan of the POB rich composition, the endothermic peak shows obscurely and enthalpy of fusion becomes small due to the change in the crystalline morphology from isotropic to anisotropic. In general, the melting point of copolyesters is increased by the solid-state polymerization reaction. It is also found that both the melting temperature and enthalpy of fusion of the copolyesters can be increased simultaneously by the solid-state polymerization reaction only when the composition of POB/PET is 80/20. This phenomenum at this composition may be attributed to the annealing effect caused by the randomness of two moiety units on the backbone chain of copolyesters and the increased molecular weight as well. © 1994 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 52 (1994), S. 869-873 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Polyurethanes were synthesized from polyester polyols, derived from PET Waste. The PET waste was first depolymerized by glycolysis. The glycolysized products were reacted with adipic acid to yield polyester polyols, and the polyester polyols were then reacted with either MDI or TDI to obtain polyurethanes. In this article, the thermal properties of the polyurethanes obtained are discussed in detail. © 1994 John Wiley & Sons, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 56 (1995), S. 1107-1112 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Poly(ethylene terephthalate) (PET) was blended with four different kinds of co[poly(ethylene terephthalate-p-oxybenzoate)] copolyesters, designated P28, P46, P64, and P82, with the level of copolyester varing from 1 to 15 wt %. All samples were prepared by melt-mixing in a Brabender Plasticorder for 8 min. The crystallization behavior of samples were then studied via DSC. The results indicate that these four copolyesters accelerate the crystallization rate of PET in a manner similar to that of a nucleating agent. The acceleration of the PET crystallization rate was most pronounced in the PET/P28 blends with a maximum level at 10 wt % of P28, and in the PET/P28 blends, at 5 wt % of P82. The melting endotherm onset temperatures and the melting peak widths for the blends are comparable with those of neat PET. These results imply that the stability of PET crystalline phase in the blends does not change by blending. The observed changes in crystallization behavior, however, are explained by the effect of the physical state of the copolyester during PET crystallization as well as the content of the p-oxybenzoate (POB) moiety in corporated into the blends. © 1995 John Wiley & Sons, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 58 (1995), S. 1981-1989 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A series of co[poly(ethylene terephthalate-p-oxybenzoate)] thermotropic copolyesters were prepared by the copolymerization of poly(ethylene terephthalate) (PET) as moiety (II) and p-acetoxybenzoic acid (POB) as moiety (I). The polymeric products obtained were subjected to solid-state polymerization. Characterization of the copolyesters by thermomechanical analysis shows that properties such as the coefficient of thermal expansion, transition temperature, and maximum softening rate temperature varied directly as a function of composition as well as did solid-state polymerization time. All thermomechanical data were found to increase with the solid-state polymerization time due to the increase in the degree of polymerization and the effect of annealing. The coefficient of thermal expansion behaves in a manner that is interpretable by the crystalline state of the copolyester. The relationship between the free-volume fraction and thermodynamic properties is further correlated for a more comprehensive discussion on its molecular arrangements. © 1995 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 60 (1996), S. 1505-1515 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Polyblends of poly(butylene terephthalate) (PBT) with four different types of co[poly(ethylene terephthalate-p-oxybenzoate)] copolyester, designated as P28, P46, P64, and P82, were prepared by melt-blending. The crystallization behaviors of the blends were then studied by differential scanning calorimetry and polarized optical microscopy (POM). Crystallization rate and temperature of neat PBT are increased when less than 10 wt% of P28 is blended. On the contrary, crystallization rate and temperature of neat PBT decrease when 10 wt% of P46, P64, or P82 copolyesters is blended. The crystallization behaviors of the blends are confirmed by the POM observations at the cooling cycles of the melts. On the other hand, melting endotherm onset temperature and melting peak width for all blends are comparable with those of neat PBT. These results imply that the stability and distribution of PBT crystallites in the blends are not significantly influenced by blending. The effects of POB content in the composition of the blends on the crystalline morphology were also presented. It is found that the structure of crystallites of the blends changed gradually with increasing the POB content in the composition of copolyester from lamellar to cross-like spherulite structures. © 1996 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 61 (1996), S. 1455-1463 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Poly(ethylene terephthalate) (PET) was blended with a co[poly(ethylene terephthalate-p-oxybenzoate)] (POB-PET) copolyester which is a liquid crystalline polymer consisting of p-oxybenzoate and ethylene terephthalate units in a 40/60 mol ratio (P46). The level of P46 liquid crystalline polymer varies from 10 to 50 wt %. All the blends were prepared by melt-mixing in a Brabender Plasticorder at 275°C for different times. The thermal and crystallization behaviors of blends depend on the blending time and the composition of blends, viz., the content of the p-oxybenzoate (POB) moiety incorporated into the blends. The interchange reactions detected by proton NMR analysis occur during the processing at a greater level if the blending time increases. The interchange reactions hinder the crystallization processes of PET and result in a decrease of the melting point, the heat of fusion, crystallization temperature, and the heat of crystallization of the original PET. The effects of the interchange reaction on thermal and crystallization behaviors of the blends may be attributed to the insertion of the rigid POB units into the soft PET chain. © 1996 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 54 (1994), S. 1223-1231 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The dynamic and isothermal crystallization behaviors of polyethylene terephthalate (PET) blended with two types of co[poly(ethylene terephthalate-p-oxybenzoate)] copolyesters with different compositions, i.e., POB/PET = 20/80 (P28) and POB/PET = 80/20 (P82), has been studied by using differential scanning calorimetry (DSC). Both of these copolyesters in 10 wt % increase crystallization rate of PET in a manner similar to that of a nucleating agent. It is found that sample P28, which is an isotropic copolyester, accelerates the crystallization rate more significantly than that of P82, which is a thermotropic copolyester. The Avrami exponents n and rate constants k of these samples based on DSC studies were obtained in order to discuss the crystallization kinetics of PET accelerated by these copolyesters. The crystallization rate of the blends is also increased by 8 min blending due to the increased uniformity of the copolyester dispersed in the PET matrix. © 1994 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 55 (1995), S. 1271-1273 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...