ESR6 - Fundamentals of Dry Strength mechanisms

Name: Mengxiao Zhao

ESR no.: 6

Description of the IRP:

The objective of this research project is to develop a deeper understanding on how chemicals can influence the dry strength of biocomposites, in our case board and tissue. The following parameters will be considered:

  • Influence of chemistry (mainly polyelectrolytes, PE) on bond and network strength
  • Influence of PE configuration and loading (charge) on bond and network strength
  • The limitations of chemistry on bond strength as fiber failure begins
  • Influence of pressing and drying
  • Influence of salt content (inorganic components) and natural polymers (organic components) in the matrix where bonds are formed (= influence of process conditions)

We are aiming to develop a holistic understanding on the application of chemicals for the strength improvement of paper as both molecular and macroscopic scales

  • Develop and apply the methods for studying the influence of chemical additives on both out-of-plane and interfacial shear strength in paper
  • Establish the influence of the fibre network and production process on the performance of chemical additives as strength enhancer

This research will help with our customer needs:

  • Lightweigtning of board (folding box-board, liner, fluting) made of virgin fibers and/or recycled fiber
  • More economic approach for improving the strength properties of fibers, e.g. possibilities to replace virgin long fibers with short fibers
  • More efficient recycling of paper and board; possibility to utilize recycled fiber of lower quality


  • Fiber bonding; strength additives;fiber charge; dry strength

About the ESR:

I am Mengxiao Zhao and I come from China. I studied with Pulp and Paper Engineering major from my bachelor studies. Nanocellulose was one of the key words in my bachelor thesis, it was about “Preparation of nanocellulose by hydrolysis acid and its application in papermaking”. Then after that, I went to South China University of Technology to complete my Master’s degree. During my master study, I was supported by Trinseo company to study in Abo Akademi University in Turku, Finland. There, I did research with ”Hemicellulose and acetylated hemicellulose as binder in pigmented coatings”. I am very good at characterization of paper and polymers, such as tensile strength, IGT, optical properties, GC, HPLC, SEM, DSC. I like sports very much, especially hiking in forest and sea side. Learning violin is also my hobby now. Besides, I am very positive and always bring happiness to people who are around me.


Contact information:

  • Mengxiao Zhao
  • Kemira Oyj, Fiber & Bioeconomy
  • Luoteisrinne 2, P.O.Box 44, FI-02271 Espoo, Finland  
  • +358 40 485 3002