Development of high‐strength fibers from aliphatic polyketones by melt spinning and drawing

Abstract

ABSTRACT:We have investigated the formation of high-strength, high-modulus fibers from four aliphatic polyketone resins. One resin was a perfectly alternating copolymer of ethylene and carbon monoxide, while the other three were terpolymers containing up to 6 mol % propylene. The mechanical properties were measured as a function of processing conditions, and the structures of the filaments were characterized using birefringence, WAXS, SAXS, SEM, and thermal analysis. Fibers formed from all resins develop very high molecular orientations and a microfibrillar structure. Fibers having room temperature tenacities as high as 10 gpd (ϳ1.1 GPa) were obtained. Tensile moduli reached values as high as 120 gpd (ϳ13 GPa). The melting point of the fibers was primarily dependent on the composition of the resin, while the maximum strength and modulus were largely determined by the maximum draw ratio achieved. The maximum draw ratio achieved in the present experiments was greater for the terpolymers than for the copolymer.

Progress in polyketone materials: blends and composites

“…Structurally, the processes of spinning, drawing and annealing lead to the transformation of the unoriented β ‐phase‐rich fibers into oriented α ‐phase‐rich fibers . Similar results have also been revealed in the high‐speed injection‐molding process .…”

“…Melt spinning is generally preferred over solution spinning. For melt spinning methods, the first example was provided by Gupta et al , where POK fiber was obtained with an elongation at break as high as 540%. Electrospinning is a powerful method for preparing fibers with diameters ranging from a few micrometers to nanometers and Ohsawa et al were the first to prepared POK‐E nanofibrous membrane using electrospinning from solution.…”

“…This transformation was attributed to the cooling rate of the melt spun and drawn filaments. Higher cooling rate of the melt spun filaments allows much of the β ‐phase to be retained, while relatively slower cooling rate of the drawn fibers such as spinning and drawing provides sufficient opportunity for the allotropic transformation from β ‐phase to α ‐phase to occur, in particular at low draw rate …”

Comparing Crystallization Kinetics between Polyamide 6 and Polyketone via Chip‐Calorimeter Measurement

“…The sample of PA was also the commercial HYOSUNG 1011 BRT (molecular weights around 20 KDa, T m ≈ 224.1 °C, T g ≈ 47 °C) . The equilibrium melting point of β‐form aliphatic terpolymer PK was reported as 252 °C and the heat of fusion for 100% crystalline β‐form PK was 227 J g −1 , while the equilibrium melting point of α‐form polyamide 6 was 250 °C and the heat of fusion for 100% crystalline α‐form polyamide 6 was 230 J g −1…”

High Performance Poly(1-oxotrimethylene) Fibers by Gel Spinning Method Using Aqueous Composite Metal Salt Solutions

“…2,3 However, the mechanical properties of the melt spinned fibers do not significantly differ from those of PET fibers widely used as industrial materials.…”