Preparation and properties of polytetrafluoroethylene/CaCO₃ hybrid hollow fiber membranes

Abstract

A novel method of preparing polytetrafluoroethylene (PTFE) hollow fiber membrane was presented by utilizing poly (vinyl alcohol) (PVA) can form a gel of two dimensional complex compounds with Boric acid (H 3 BO 3 ). Effects of H 3 BO 3 on PTFE nascent hollow fiber were investigated, and the results showed that the introduction of H 3 BO 3 effectively reduced the addition of PVA. The configuration named ''fibril'' formed between PVA and H 3 BO 3 could be observed in nascent hollow fiber by SEM (Scanning electronic microscopy). Furthermore, Calcium carbonate (CaCO 3 ) particles (60 nm$ 90 nm) were introduced into PTFE matrix. The interfacial microvoids (IFMs) which were different from the PTFE sintering or node-fibril network structure were obtained. The assumption of the IFMs formation was proposed in this study. Effects of CaCO 3 amount and draw ratios on structure and properties of hybrid hollow fiber membranes were analyzed, and the SEM results showed that the IFMs quantity and diameter improved with draw ratio increasing.

Dual‐bonding structured ternary composite film of poly(vinyl alcohol)–boric acid–nanodiamond

“…According to FTIR analysis, the vibration of hydroxyl groups weakened while BA mingled in PVA or on DND, and the peaks for BOC or COC bonding were strengthened. These results show that the hydroxyl species of the components bonded and dehydration occurred amid the crosslinking process, resulting in the construction of oxo‐bridges …”

“…These results show that the hydroxyl species of the components bonded and dehydration occurred amid the crosslinking process, resulting in the construction of oxobridges. 8,33,34 Application Properties of Composite Films Mechanical Properties of PVA Films. Table I shows the data of tensile strength (r max ), elongation at break (E max ), and Young's modulus (E) for pure PVA film and composite films of PVA/ BA, PVA/DND, and PVA/BA/DND, and curves illustrating r-E relationship and the influence of the BA-modified DND content on the E value of the films are shown in Supporting Information S3.…”

Effect of Stretching Parameters on Structure and Properties of Polytetrafluoroethylene Hollow‐Fiber Membranes

“…The maximum pore size ( D max ) was measured using the gas bubbling method and calculated by the following Eq. 5 25: …”

“…As is well‐known, each step of the paste extrusion process is critical in determining the final membrane properties. Furthermore, stretching is supposed to be the key step for porous structure formation 22–25. Kitamura et al studied the formation mechanism of porous structures in PTFE membranes by microscopy 26.…”

Preparation and properties of porous polytetrafluoroethylene hollow fiber membrane through mechanical operations

“…Kawai in Japan provided the method and porous PTFE hollow fiber membrane with pores of 0.3–2.0 µm, porosity of about 40%. Huang in China did much works on PTFE hollow fiber membrane (porosity 38.6%, water contact angle 134.68°) to reduce the addition of fiber‐forming polymer and obtain the porous microstructure of interfacial microvoid. As a result of above studies about emulsion spinning, it is found that the membrane product suffers from inferior porosity and permeability performance.…”