Research Experience

Affiliation: Smart Polymers & Composites Laboratory, University of Toronto

Supervisor: Prof. Hani Naguib | Duration: Nov 2024 – Aug 2025

Industry Partner: (Confidential)

This project focused on developing and optimizing multilayer thermoplastic composite pipe systems for use in extreme environments such as electrical infrastructure, energy pipelines, and industrial processing systems. The study addressed three key challenges — high-temperature stability, interfacial adhesion, and cost reduction — across the outer jacket (PPS-based), tie layer (Orevac-based), and inner liner (PERT-based) materials.

The goal was to establish material design and processing strategies that balance mechanical strength, adhesion reliability, and cost efficiency, supporting the industrial partner’s transition toward sustainable, high-performance polymer piping systems.

The research followed a layer-by-layer evaluation combining experimental testing, material compounding, and thermal–mechanical analysis:

• Outer Layer (PPS XE5000NA and AX8840 Blends):

  • Compared old vs. new PPS XE5000NA formulations via isothermal rheology at 300 °C.

  • Conducted DMA temperature-ramp studies (RT – 160 °C) to identify the critical AX8840 compatibilizer threshold (~19 wt%), beyond which modulus declined due to loss of crystalline continuity.

  • Outcome: The new PPS grade demonstrated superior viscosity stability and stiffness retention, confirming its suitability for high-temperature jackets. 

• Tie Layer (Fiber-Reinforced Orevac 18722):

  • Fabricated PPS–Orevac–PPS multilayer laminates with 3 wt% and 6 wt% reinforcement (CF, PPS fibers).

  • Performed peel tests (RT and 95 °C) using Anton Paar DMA and TMA-based CTE analysis.

  • Found that neat Orevac exhibited the highest adhesion (15.3 N @ RT; 31.1 N @ 95 °C), while fiber reinforcement reduced chain mobility and stress relaxation.

  • Proposed a mechanism linking temperature-dependent cohesive transition to residual stress relaxation and polymer chain mobility. 

• Inner Layer (Reinforced PERT Composites):

  • Compounded PERT with CF, TF, GF fibers and compatibilizers (Polybond and Nova Sclair) using twin-screw extrusion and injection molding.

  • Conducted DMA frequency sweeps, tension/torsion tests, and cyclic damage experiments to assess stiffness, anisotropy, and durability.

  • Identified PERT-15 wt% Technora fiber (TF) as the best-performing formulation, offering balanced stiffness and modulus retention, while Nova Sclair improved rigidity and Polybond enhanced tensile strength.

  • Demonstrated carbon fiber composites with tensile moduli > 4 GPa, approaching PPS performance under axial loading.

• Outer Layer: New PPS formulation showed improved thermal stability and modulus retention up to 300 °C; AX8840 threshold ≈ 19 wt%.

• Tie Layer: Adhesion strength doubled from RT to 95 °C due to stress relaxation; cohesive failure initiated beyond 50 °C; fiber reinforcement decreased peel strength.

• Inner Layer: PERT-15TF achieved optimum stiffness–ductility balance; CF > TF > GF in stiffness, but TF composites showed superior modulus retention under cyclic loads.

• Processing Influence: Injection molding induced anisotropy (E/G ≈ 6.2), while compression molding produced uniform mechanical response.

• Compatibilizer Effects: Nova Sclair → stiffness (2437 MPa); Polybond → strength (55.5 MPa); no synergy when combined.

• Durability: Technora-reinforced PERT composites maintained >85% modulus retention under progressive stress cycling.

• Polymer Compounding & Processing: Twin-screw extrusion, compression molding, injection molding

• Thermal & Mechanical Testing: Rheometry, DMA, TMA, peel testing, cyclic tensile testing

• Material Characterization: Thermal expansion (CTE), viscoelastic behavior, failure mode analysis

• Data Analysis & Optimization: Modulus retention modeling, compatibilizer–reinforcement trade-off mapping

• Collaboration: Industrial R&D coordination under Prof. Hani Naguib’s supervision

Presentation