Polymer physics + engineering distinct from polymer-chemistry: molecular-weight distribution, Flory-Huggins phase, glass-transition, viscoelasticity, processing (extrusion / injection / 3D-print), composites, degradation, recycling.
polymer-physics-and-engineering
Flory MW distribution + Schulz-Flory
Flory 1936-53: living-polymerisation gives Poisson MW-distribution; condensation gives Schulz-Flory (Mw/Mn = 2). Step-growth vs…
Flory-Huggins phase diagram (cross-listed)
Cross-listed L2 tissue-engineering Flory-Huggins hydrogel. Polymer-solvent miscibility predicted by χ-parameter + entropy of mixing.…
Glass transition Tg + WLF equation
Glass-transition: amorphous polymer reversibly transitions liquid-vs-glass at Tg. Williams-Landel-Ferry (WLF) 1955: viscosity…
Viscoelasticity (Maxwell / Voigt models)
Maxwell 1867: spring-dashpot in series, stress-relaxation. Voigt: parallel, creep. Generalised Maxwell + WLF. Foundation of…
Rouse + reptation (de Gennes)
Rouse 1953 unentangled-polymer dynamics; de Gennes 1971 reptation for entangled. Diffusion τ ∼ N² (Rouse) vs N³ (reptation). Cross-listed…
Polymer extrusion (twin-screw)
Co-rotating twin-screw extruder: zone-controlled melting + mixing + venting + die-shaping. Reactive-extrusion enables in-line…
Injection moulding + fountain flow
Plasticate + inject + cool + eject cycle. Fountain-flow at advancing-melt-front. Mould-filling simulation (Moldflow). Residual-stresses +…
3D printing polymers (FDM / SLA / SLS)
Hull 1986 SLA stereolithography; Crump 1989 FDM; SLS selective-laser-sintering. Layer-by-layer additive-manufacturing of polymers.…
Composite materials (fiber-matrix)
CFRP carbon-fiber-reinforced-polymer + GFRP. Hashin failure-criteria; mixture-rules for properties. Aerospace (Boeing 787 ~50% composite).…
Polymer degradation (UV / thermal / biological)
Norrish photo-degradation; thermal-oxidation chain-cleavage; Hydrolytic / enzymatic-degradation. Stabilisers (HALS / antioxidants) extend…
Polymer recycling + circular polymers
Mechanical (re-melt) vs chemical (de-polymerise + re-polymerise) recycling. Sun 2017 / Hong 2020 closed-loop CRPs. Bottle-grade rPET. EU…
Biopolymers + biodegradable (PLA / PHB / PHA)
Lactic-acid-derived PLA (NatureWorks); microbial PHB / PHA (Metabolix). Compostable under industrial-conditions. Cross-listed L3…
Flory-Huggins chi (1942)
Flory-Huggins 1942: Delta-G/RT = phi_1 ln phi_1 / N_1 + phi_2 ln phi_2 / N_2 + chi phi_1 phi_2; basis of polymer-blend miscibility + UCST.
Rubber elasticity (Treloar 1949)
Kuhn 1934 + Treloar 1949 entropic-elasticity: F ~ kT/N for chain extension; vulcanization crosslinks set network elasticity; G = nkT for…
Rouse-Zimm dynamics (1953)
Rouse 1953 unentangled chain-bead-spring + Zimm 1956 hydrodynamic-interactions; Tg + viscosity scaling laws; modern reptation Doi-Edwards…
Tg WLF equation (1955)
Williams-Landel-Ferry 1955: log a_T = -C1(T-T_ref)/(C2+T-T_ref); time-temperature superposition; C1 ~17 + C2 ~52 K universal at Tg-ref;…
Step- vs chain-growth (Carothers)
W Carothers 1929 step-growth nylon vs chain-growth polymerization distinction; Flory 1936 statistics; gel-point Stockmayer 1944; Mn =…
Reptation (de Gennes 1971)
P G de Gennes 1971 (Nobel 1991) reptation: chain confined to tube of entanglements; t_rep ~ N^3 (vs Rouse N^2); explains…