Basics

A Common thermoplastic
Also known as:
- Poly(methyl methacrylate)
- PMMA
- acrylic glass
- plexiglass
- the trade names Crylux, Plexiglas, Acrylite, Astariglas, Lucite, Perclax, and Perspex
Is often clear
Is also a waste product from some sites (offcuts from laser cutters etc)
Can also be made into a Bubblegram which only it, and glass can do
VERY easy to work with:
- Can be laser cut if in sheet form
- Melts ~160 °C near PLA and ABS
- Doesn'thave the hydrolysis issues of PET
Altogether GREAT material
It is a plastic, but supposedly some organisms may be evolving to break it down:
- From wikipedia:
  - The Futuro house was made of fibreglass-reinforced polyester plastic, polyester-polyurethane, and poly(methylmethacrylate); one of them was found to be degrading by cyanobacteria and Archaea

Sourcing

Black, Ebay, $5/sf, 1/8" - [1]
Menards 3 sf, 0.08 - $3/sf - [2]
6 Square feet - $6/sf + shipping - [3]
$23/sq ft, 1/4" - [4]
$9/sf - 1/4" - https://www.mcmaster.com/#acrylic/=1653xn3
2x4 - 1/8" - $37 - [5]
$6/sf - 1/4" - https://www.menards.com/main/building-materials/acrylic-glass-sheeting/clear-colorless-acrylic-sheets/p-1444441881915.htm
$4/sf - 0.1" - Sutherlands - [6]

You can get 1/32" polycarbonate, 4x8 sheets, at about $70. This is about $2/sf. Would need appropriate structural support, but otherwise it's pretty much indestructible.

Varying methods
The main route seems to be Methyl methacrylate + A Polymerization Catalyst such as methyl ethyl ketone peroxide (MEKP)
- This is mainly done for "casting" the artificial "resin", but could perhaps be done in a reactor for producing solid string-ey product, for further refining into FDM Filament or Plastic Pellets
The "easiest" to do seems to be the various "Methyl propionate routes"
- Uses carboalkoxylation of ethylene to produce methyl propionate (MeP)
- Followed by the MeP being condensed with formaldehyde in a single heterogeneous reaction step to form MMA
So needs:
- Ethylene
- Formaldehyde