Grafting of chloromethylstyrene to polypropylene fibers by the use of ionizing radiation

Abstract

Chloromethylstyrene monomer was grafted to 3 denier (preformed) polypropylene fibers by using ionizing radiation. At elevated temperatures, microscopical investigations of changes in diameter and in birefringence demonstrated that this monomer swells the fibers without dissolving them. Thus, it is comparatively simple to achieve grafting all the way to the center. Such grafted fibers can be dyed by direct or acid dyes in non‐aqueous baths (e.g., dimethylformamide at 210°C.) using levels of graft of ∼25% by weight. This leads to covalent bonding arising from reaction between the dye and the benzyl chloride group of the graft. Dyeing in standard aqueous baths can also be achieved at even lower levels of graft (less than 10% by weight) if the grafted material is treated with a nucleophilic reagent such as pyridine. Using thin cross sections of treated fibers, photomicrographs were taken with monochromatic UV radiation, and with visible light on color film. These, combined with electron micrographs of much thinner cross sections provide pictorial proof of the complete penetration of the graft and of the dyes as well as showing the opening up of the structure effected by grafting. By the means employed, it was possible to achieve marked improvements in dyeability, sticking temperature, moisture regain, and antistatic behavior without diminishing the excellent mechanical properties of the polypropylene fibers.

Influence of the structure of polypropylene fibers on the rate of grafting and the structural changes caused by grafting

“…There are some references to the influence of the crystallinity of polyolefins on their grafting, such as the papers of Sobue and Tajima (4), Dob6 and his co-workers (51, Stamm and his co-workers (6), and Ballantine and his co-workers (71, but they are without the support of experimental evidence. The work of Vlasov, Cetlin and others (8)(9)(10)) is remarkable.…”

Electron Microscopy

“…Synthetic fibers, once thought to be homogeneous, have been recognized as being composed of primary and secondary structures (31,98,229,400). There are also wide varieties of chemically modified physically treated, delicately coated and intimately coordinated fibers (55,56,57,118,390,391,433,515). When chese complexities are added to those of integration and fabrication, it becomes evident that an investigator must analyze his problem and plan his microscopical research with due regard to the number and relationship of molecular associations present, using a classification scheme such as that proposed by Rochow (387,388,389).…”

Studies on Reactions of Polypropyrene. VI. The Thermal Degradation of Polypropylene Accelerated by the Fine Powdery Polymer with Closslinkage

“…Therefore, many processes have been proposed to overcome these drawbacks. [1][2][3][4][5][6][7][8][9][10] In the thermal degradative process accelerated by such vinyl polymers as polystyrene and polymethyl methacrylate, graft or block copolymers were formed, and the poor dyeability of polypropylene could be modified.11) However, some of the vinyl polymers used in this process were extractable by acetone, and it was considered to be undesirable for practical use.…”