This is small demonstration about how you can make a sentiment analysis for product reviews. I utilized Bing and AFINN dictioneries in the sentiment analysis.
Here I used Amazon store reviews for Amazon Kindle, a tablet mainly for reading ebooks. I used Kaggle data, which means you can easily replicate the analysis by yourself. The review dates start from 2015 and go through 2018. In the data set, there are also 41 more products with a varying degress of review rate.
Here is the md file to see the process and graphs