Further Studies of Mechanical Damage on Machine-Harvested Cotton Fiber via Coupling Effect of Moisture Regains and Low Temperature

Figures & data

Figure 1. Breaking force curve of cotton individual fiber and the illustration is fracture interface morphology.

Figure 2. Schematic representation for the steps of experimental.

Table 1. Tensile mechanical properties result in normal machine-harvested cotton fibers.

Average of 15 data [standard variations]	Breaking Force/cN	Fracture Strength/cN·tex^−1	Time at Break/s	Elongation at Break/%
N-HMR	4731.08[7.66]	36.39[7.66]	0.31[10.93]	8.1[10.53]
N-LMR	4149.22[6.39]	31.92[6.39]	0.28[11.17]	7.4[11.01]
Normal	4326.85[7.58]	33.28[7.58]	0.29[10.78]	7.7[10.67]

Table 2. Tensile mechanical properties result in low temperature machine-harvested cotton fibers.

Average of 15 data	Breaking Force/cN [standard variations]		Fracture Strength/cN·tex^−1 [standard variations]		Time at Break/s [standard variations]		Elongation at Break/% [standard variations]
	L-HMR	L-LMR	L-HMR	L-LMR	L-HMR	L-LMR	L-HMR	L-LMR
TL=-20°C	3137.7 [9.63]	3002.66 [9.24]	24.14 [9.63]	23.1 [9.24]	0.29 [12.92]	0.32 [12.58]	5.3 [12.57]	5.6 [12.88]
TL=-15°C	3593.9 [9.16]	3297 [8.68]	26.11 [9.16]	25.36 [8.68]	0.28 [12.89]	0.35 [12.76]	5.5 [12.98]	5.9 [12.62]
TL=-10°C	3296.03 [8.65]	3454.3 [8.02]	25.35 [8.65]	26.57 [8.02]	0.37 [12.25]	0.35 [12.43]	6.6 [11.87]	6.5 [11.81]
TL=-5°C	3750.1 [9.32]	3608.6 [8.13]	28.85 [9.32]	27.76 [8.13]	0.34 [12.08]	0.37 [12.53]	6 [11.51]	6.7 [11.25]
TL = 0°C	3980.4 [7.87]	4078.03 [6.62]	30.62 [7.87]	31.37 [6.62]	0.39 [11.99]	0.35 [11.83]	6.9 [11.62]	7.3 [11.36]

Figure 3. Fiber breaking force curve of machine-harvested cotton in low temperature environment. (a) L-HMR fiber experimental curve and fitting curve, (b) L-LMR fiber experimental curve, and fitting curve.

Table 3. MATLAB parameters and results.

Parameter	Parameter estimate	Parameter confidence interval
a0	3994.133713	[3778.083991, 421.183434]
a1	69.248714	[26.779215, 111.718213]
a2	1.210486	[−.825771, 3.246742]
a3	1.321236	[−8.249857, 1.892329]

Figure 4. Linear correlation between temperature, moisture regain and mechanical properties.

Figure 5. Elongation at break variation trend of machine-harvested cotton in low temperature environment.

Figure 6. Fracture morphologies of machine-harvested cotton fibers in different environments. (a) N-HMR sample fracture interface morphology, (b) N-LMR fracture interface morphology, (c) −20°C L-HMR sample fracture interface morphology, (d) −20°C L-LMR sample fracture interface morphology.