Untitled

Abstract

The low number of distinct dislocation slip systems (two) is characteristic of a brittle material and is consistent with the observation that paracetamol will tolerate only deformations of 1 part in 10(6) before fracture.

Mesoscale modeling of dislocations in molecular crystals

“…In Section 4, we show the results of our simulations of plastic deformation of paracetamol and sucrose single crystals. Our simulations reproduce a yield stress y $ 200 MPa for paracetamol and y $ 1 GPa for sucrose, in good agreement with experimental observation [23][24][25].…”

“…We simulated stress-strain curves for different values of slip plane distances. Our simulations show that a slip plane distance d ¼ 2b 1 ¼ 1:88 nm gives a yield stress y ¼ 150-250 MPa, which is a good estimate of the value of the yield stress observed in experiments, y $ 200 MPa [24]. Therefore, we assume that the slip plane distance is d ¼ 9.4 nm.…”

“…Figure 1 shows its crystalline structure. DuncanHewitt et al [23] and Finnie et al [24] [21]. The (010) plane has a herringbone structure in the [100] direction and slip occurs in a sequence of partial motions across the corrugation with Burgers vector of magnitude jb 2 j ¼ 1:293 nm, see Figure 1.…”

“…Most of these experiments in sucrose and paracetamol concentrate on hardness measurements [18][19][20][21][22][23][24]. A few among these references include information on dislocation activity in paracetamol [21,23,24]. More recently, Ramos et al [25] conducted detailed indentation studies on sucrose to identify anisotropy and dislocation activity.…”

Indentation Plasticity and Fracture Studies of Organic Crystals

“…However, in the case of the butyl paraben, longer and more bulky alkyl chains provide resistance to the gliding of the slip planes; therefore, higher hardness compared to the ethyl and propyl parabens were observed. Duncan-Hewitt et al [101] and Finnie et al [102] performed indentation studies on paracetamol (acetaminophen) and revealed that the hardness varied as a function of indenter orientation with the crystallographic direction within the indentation planes. …”