# Photodegradation of Acrylic Polymer

#### Myles P. Murray, Donghui Li, Hein Htet Aung, Roger H. French, Laura S. Bruckman

#### 2026-02-24

## Data Description

The data set is a study of photodegradation of acrylic polymer. In this work, polymeric samples were exposed to different levels of light exposures and resulting optical changes were determined through optical spectroscopy. YI (yellowness index) is the main endogenous variable and all other columns in the data set IrradTot (total applied irradiance), IAD1, IAD2, IAD2p, and IAD3 are considered as exogenous variables, with fully consideration of the nonrecursive “feedback loop” relations.

## Load data and run code to build netSEM

    ## Load the acrylic data set
    data(acrylic)
    ?acrylic

    ## Run netSEMp1 model
    ans1 <- netSEMp1(acrylic, exogenous = "IrradTot", endogenous = "YI")
    ## Plot the network model for principle 1
    plot(ans1, cutoff = c(0.3,0.6,0.9))

    ## Run netSEMp2 model
    ans2 <- netSEMp2(acrylic, exogenous = "IrradTot", endogenous = "YI")
    ## Plot the network model for principle 2
    plot(ans2, cutoff = c(0.3,0.6,0.9))

## Network diagram for data

Acrylic netSEMp1 model

Acrylic netSEMp2 model

## Reference

Myles P. Murray, Laura S. Bruckman, and Roger H. French “Photodegradation in a stress and response framework: poly(methyl methacrylate) for solar mirrors and lens,” Journal of Photonics for Energy 2(1), 022004 (19 November 2012). https://doi.org/10.1117/1.JPE.2.022004