Crystallinity and Crystal Order in Ramie Cellulose Treated by Caustic Soda

Herrn Professor Dr. Horst Frommelt zum 60. Geburtstag gewidmet 111 Abhangigkeit von der durch Natronlaugenbehandlung hervorgerufenen Gitterumwandlung werden Veranderungen der ubermolekularen Struktur von Linters-Cellulose durch geeignete Parameter (Kristallinitatsgrad, Ordnung und Groile der kristallinen Bereiche) charakterisiert. Die Anwendung des Verfahrens nach RULAND-VONK zur Kristallinitatsgradbestimmung sowie einer Methode zur Bestimmung lateraler Kristallitabmessungen unter Verwendung von PEARSON-VII-Funktionen zur Peakseparation wird beschrieben. Die Ergebnisse werden auf der Grundlage des Modells uneinheitlicher Fransenfibrillen fur die Cellulosestruktur diskutiert. JIccdoeanuR no naanoneqmpnoii cmpyKmype npu gaaoeon nepexoae yenAwnoaa6 I -I I nemoaom penmenoecnoeo paccesnua na 60nbwue yam c IIOMOU(blo I I O~O~U X UapaMeTpOB (KpUCTaJIJIHYHOCTb, YUaKOBKa U BeJIHUHHa KPHCTaJIJIkiYeCKUX 06nac~eti) OXapaKTepH3OBalrnr U3MeHeHUR HE4(MOJIeKyJIJTpHOB CTPYKTYPM qeJlJIIoJI03bI XJIOIIKOBOrO IIyXa B 3aBUCUMOCTU OT B03AefiCTBUR PaCTBOpa eAKOr0 HaTpllR. OIIHCaHO IIpHMeHeHHe MeTOAaPYJIAHAA-@OHKA AJIR OllpeAeJIeHllH KpHCTaJIJIHY-HOCTU U MeTOAa AJIR OIIpeAeJIeHHR JIaTepUIbHblX pa3MepOB KpHCTaJIJIUTOB C IIOMOUJbH) nHPCOH-VII-@yHKqHefi AJIR OTAeJIeHHJT MaKCUMyMOB. PeayJIbTaTbI ~W I U HHTepIIpeTHpOBaHbI H a OCHOBe MOAeJIU HeCOBePUeHHbIX 6axpOMOBHX @ i 6 p~n n o~ qennlono3~oi4 C T~Y K T Y~H .Wide angle x-ray investigation on the supermolecular structure at the cellulose I -cellulose I I phase transition I n dependence of a lattice transformation caused by.treatment with aqueous alkali t h e changes of the supermolecular structure of linters-cellulose are characterized by suitable parameters (degree of crystallinity, order and size of crystalline regions). The application of t h e RULAND-VONK-method for determining the degree of crystallinity as well as of a procedure for calculating lateral crystallite sizes involving peak separation by means of PEARSON-VII-functions is described. The results are discussed on the basis of non-uniform fringed fibrils as a model for the cellulose structure.

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Thermal properties and crystalline structure of liquid crystalline poly(ethylene terephthalate‐co‐2(3)‐chloro‐1,4‐phenylene terephthalate)

Rhee¹,

Youk

et al. 2002

J of Applied Polymer Sci

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Thermal properties and crystalline structure of liquid crystalline (LC) poly(ethylene terephthalate-co-2(3)-chloro-1,4-phenylene terephthalate) [copoly(ET/ CPT)] were investigated using differential scanning calorimetry (DSC), thermogravimetry (TGA), limiting oxygen index (LOI) measurement, electron dispersive X-ray analysis (EDX), X-ray diffractometry, and infrared spectrometry (IR). The thermal transition temperatures of copoly(ET/CPT) were changed with the composition. Copoly(ET/ CPT) showed two thermal decomposition steps and the residues at 700°C and LOI values of copoly(ET/CPT) were almost proportional to its chlorine content. The activation energy of thermal decomposition of LC units was very low compared to that of poly(ethylene terephthalate)(PET) units. Crystal structure of copoly(ET/CPT) (20/80) was of triclinic system with the lattice constants of a ϭ 9.98 Å , b ϭ 8.78 Å , c ϭ 12.93 Å , ␣ ϭ 97.4°, ␤ ϭ 96.1°, and ␥ ϭ 90.8°, which is very close to that of poly(chloro-pphenylene terephthlate) (PCPT) with the lattice constants of a ϭ 9.51 Å , b ϭ 8.61 Å , c ϭ 12.73 Å , ␣ ϭ 96.8°, ␤ ϭ 95.4°, and ␥ ϭ 90.8°. When copoly(ET/CPT)(50/50) was annealed at 220°C in vacuum, crystallization induced sequential reordering (CISR) was not observed but the heat of fusion was slightly increased due to the increase of the trans isomer content in PET units.

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Crystallinity and Crystal Order in Ramie Cellulose Treated by Caustic Soda

Cited by 4 publications

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Physical Constants of Cellulose

Physical Constants of Cellulose

Röntgen‐Weitwinkeluntersuchungen zur übermolekularen Struktur beim Cellulose‐I‐II‐Phasenübergang

Thermal properties and crystalline structure of liquid crystalline poly(ethylene terephthalate‐co‐2(3)‐chloro‐1,4‐phenylene terephthalate)

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