Self-reinforced Poly Ethylene Terephthalate Research Articles

Assessing PET composite prosthetic solutions: A step towards inclusive healthcare

The demand for affordable prostheses is particularly high in Low Middle-Income Countries (LMICs). Currently, sockets are predominantly manufactured using monolithic thermoplastic polymers, which lack durability and strength, or consumptive thermoset resin reinforcing with expensive composite fillers like carbon, glass, or Kevlar fibers. However, there exist unmet and demanding needs among amputees for procuring low-cost, high-strength, and faster socket manufacturing methods. We evaluate a socket made from a novel manufacturing technique utilizing an affordable and sustainable composite material called commingled PET (polyethylene terephthalate) yarn, along with a reusable vacuum bag, to produce custom-made sockets in a purpose-built curing oven. Our innovative fabrication methodology enables the production of complex-shaped patient sockets in under 4 h. To evaluate the efficacy and performance of the PET sockets, we conducted trials with both unilateral and bilateral amputees over a six-month period, in collaboration with Bhagwan Mahaveer Viklang Sahayata Samiti (BMVSS) in India. Utilizing a 6-min walking test, we measured various gait parameters, including ground reaction forces and flexion angle, for both unilateral and bilateral amputees.The gait analysis conducted on amputees using our PET-based sockets demonstrated their ability to engage in daily activities without interruptions, reaffirming the functional efficacy of our approach. By combining self-reinforced PET with our novel fabrication technique, we offer a unique and accessible solution that benefits clinicians and patients alike. This study represents significant progress towards achieving affordable and personalized prostheses that cater to the needs of LMICs.

Single Polymer Composites: An Innovative Solution for Lower Limb Prosthetic Sockets

The demand for affordable prostheses, particularly in low- and middle-income countries (LMICs), is significant. Currently, the majority of prosthetic sockets are manufactured using monolithic thermoplastic polymers such as PP (polypropylene), which lack durability, strength, and exhibit creep. Alternatively, they are reinforced with consumptive thermoset resin and expensive composite fillers such as carbon, glass, or Kevlar fibres. However, there are unmet needs that amputees face in obtaining affordable prosthetic sockets, demanding a solution. This study utilises self-reinforced PET (polyethylene terephthalate), an affordable and sustainable composite material, to produce custom-made sockets. Advancing the development of a unique socket manufacturing technique employing a reusable vacuum bag and a purpose-built curing oven, we tested fabricated sockets for maximum strength. Subsequently, a prosthetic device was created and assessed for its performance during ambulation. The mechanical and structural strength of PET materials for sockets reached a maximum strength of 132 MPa and 5686 N. Findings indicate that the material has the potential to serve as a viable substitute for manufacturing functional sockets. Additionally, TOPSIS analysis was conducted to compare the performance index of sockets, considering decision criteria such as material cost, socket weight, and strength. The results showed that PET sockets outperformed other materials in affordability, durability, and strength. The methodology successfully fabricated complex-shaped patient sockets in under two hours. Additionally, walking tests demonstrated that amputees could perform daily activities without interruptions. This research makes significant progress towards realising affordable prostheses for LMICs, aiming to provide patient-specific affordable prostheses tailored for LMICs.

Energy absorption of all-PET 2nd order hierarchical sandwich structures under quasi-static loading conditions

The impact performance of lightweight structures represents an important design criterion in modern applications. Within this framework, the self-reinforced PET (poly-ethylene terephthalate) materials prove to exhibit large deformations till failure, which enables them to be proper candidates for impact energy absorption. Apart from the advantages offered by the lightweight characteristics, they are made of recyclable materials, an additional reason for their consideration in engineering applications. In this paper, the behavior of a hierarchical sandwich structure made out of self-reinforced PET (matrix & fibre) combined with PET foam is numerically investigated with respect to the specific energy absorption (SEA) capacity in out-of-plane quasi-static loading conditions. The numerical model of the structure is developed and its behavior is firstly validated through experimental tests. The specific energy absorption is further on determined for several geometric configurations of the hierarchical sandwich structure and compared with the behavior of other cellular structures found in the technical literature. A competitive behavior is observed with respect to impact energy absorption.

Fracture behavior and damage development in self-reinforced PET composites assessed by located acoustic emission and thermography: Effects of flame retardant and recycled PET

Self-reinforced polyethylene terephthalate (srPET) composites were produced by hot pressing from woven fabrics composed of double covered uncommingled yarns. The mid section of the latter contained recycled PET homopolymer filaments (reinforcement) whereas the covering filaments (overtaking the role of the embedding matrix) were spun from a PET copolymer with and without flame retardant. The fracture of the srPET was studied in tensile loaded notched specimens using located acoustic emission (AE), infrared thermography (IT) and visual inspection in situ. The crack growth was reconstructed by evaluating the located AE and IT results and compared with the observed one. In the knowledge of the crack propagation the J-integral resistance (JR) fracture mechanics concept was followed to characterize the fracture behavior. srPET with fire retardant matrix exhibited lower JR characteristics than the unmodified composite. This was traced to differences in the failure modes considering the amplitude distribution of the AE events and post mortem failure analysis. Size of the damage zone was estimated by considering the located AE (≈20 mm) and IT results (≈15 mm), and the related difference discussed.