Polytrifluormethylstyrole, eine polymerklasse mit aussergewöhnlichen optischen eigenschaften

Abstract

Herrn P r o f . D r . Otto B a y e r i n m e m o r i a m gewidmet ZUSAMMENFASSUNG: Homopolymerisate aus 2-, 3-und 4-Trifluormethylstyrol, 4-Perfluorisopropylstyrol, 3,5-Bis-trifluormethyIstyrol und ein 1 : 1 Copolymerisat aus 2,4und 2,5-Bis-trifluormethylstyrol wurden hergestellt und Brechungsindices, Abbe-Zahlen sowie Glasubergangstemperaturen der Polymerisate bestimmt. Von diesen Thermoplasten ist das Poly-2-trifluormethylstyrol im Hinblick auf optische Anwendungen besonders interessant, da es in einem weder von anorganischen Glasern noch von bekannten thermoplastischen Kunststoffen bisher erreichten Gebiet des n-v -Diagrammes liegt. Die wichtigsten mechanischen und thermischen Eigenschaften dieses Polymeren und die Copolymerisationsparameter fur die binare Copolymerisation von 2-Trifluormethylstyrol mit Styrol, Methylmethacrylat und n-Butylacrylat wurden bestimmt. Optische Daten und Glastemperaturen einiger Copolymerisate des 2-Trifluormethylstyrols werden mitgeteilt. SUMMARY: Homopolymers of 2-, 3and 4-trifluoromethylstyrene, 4-perfluoroisopropylstyrene, 3,5-bis-trifluoromethyl-styrene and a 1 : I copolymer of 2,4-and 2,5-bis-trifluoromethyl-styrene have been synthesized and t h e refractive indices n Abbe-numbers vD and glass transition temperatures of t h e polymers have been deylrmined.With regard to optical applications poly-2-trifluoromethyl-styrene is particularly interesting since its optical properties a r e in a region of t h e n-vdiagram t h a t has not been reached by thermoplastic polymers or inorganic glasses before.The most important mechanical and thermal properties of this polymer a r e reported Reactivity ratios of t h e binary copolymerisation of 2-trifluoromethyl-styrene with styrene, methyl-methacrylate and n-butyl-acrylate a r e listed as well as optical d a t a and glass transition temperatures of some copolymers of 2-trifluoromethyl-styrene.

Effect of trifluoromethyl substituents on birefringence of polystyrene

“…To prepare mechanically robust polymer films for the birefringence measurements, the polymerizations were carried out slowly using a small amount of AIBN (0.1 wt%) at 60°C, and high molecular weight polymers were obtained ( M w > 3.42 × 10 5 ). The T g values in Table agree well with the previous studies, which reported 175, 63, 115, and 119°C for poly(2‐TFMSt), poly(3‐TFMSt), poly(4‐TFMSt), and poly(3,5‐TFMSt), respectively . They exhibited onsets of decomposition at approximately 340°C, and the T d5 values were approximately 400°C.…”

“…Böner and Hagemann (1982) synthesized various trifluoromethyl (CF 3 )‐substituted styrenes and their homopolymers. They reported that when substitution with the CF 3 group occurs at the ortho position of PSt, the T g is considerably higher (175°C) than when it occurs at the meta or para positions ( T g s of 63 and 101°C, respectively) . This is because of the steric hindrance of the bulky CF 3 group (the van der Waals volume of CF 3 is 42.6 Å 3 compared with 16.8 Å 3 for the methyl (CH 3 ) group) at the ortho position, which results in a decrease in the segmental mobility of the polymer chains and a large increase in the T g of the PSt.…”

Rhodium‐Catalyzed Dehydrocoupling of Fluorinated Phosphine–Borane Adducts: Synthesis, Characterization, and Properties of Cyclic and Polymeric Phosphinoboranes with Electron‐Withdrawing Substituents at Phosphorus

“…The refractive index value is very close to the fluoroaryl organic analogue poly(4-trifluoromethylstyrene) which has been determined as 1.50. [34] E-beam lithography was carried out by using a converted thermionic DSM 940 (Zeiss) scanning electron microscope (SEM) with an accelerating voltage of 25 kV and controlled by a Raith ELPHY lithography system. Samples were developed through 1 min sonication in THF prior to characterization.…”

Role of surgical portosystemic shunts in the era of interventional radiology and liver transplantation

“…The thickness and refractive index of the films were characterized using ellipsometry and were determined to be 121 ± 2 nm and 1.53, respectively. The refractive index value is very close to the fluoroaryl organic analogue poly(4‐trifluoromethylstyrene) which has been determined as 1.50 34. E‐beam lithography was carried out by using a converted thermionic DSM 940 (Zeiss) scanning electron microscope (SEM) with an accelerating voltage of 25 kV and controlled by a Raith ELPHY lithography system.…”