From: [b--as--l] at [igc.org] (Ben Masel)
Date: 8 Mar 92 03:30:00 GMT
Newsgroups: talk.politics.drugs
Subject: Re: Book burning


REPOSTING:

The following two responses are abstracts of papers presented at
the First European Conference on Industrial Uses for Agricultural
Crops, held at Maastricht, The Netherlands last November.  I hope
to have the full papers soon, and will post when available.

ben

CHARACTERISATION AND PROCESSING OF ANNUAL CROPS
(ESP. HEMP) FOR PULP AND PAPER

MARIE-JOSE DE SMET

AGROTECHNICAL RESEARCH INSTITUTE, ATO-DLO,
HAAGSTEEG 6, 6700 AA WAGENINGEN (THE NETHERLANDS)

Hemp is a nonwoody annual plant containing two types of cellulose
fibers, of which one type originates from the bark, and the other
from the wood part of the stem. These fibers have different
physical properties and chemical composition. The long flexible
bast fiber which occurs in high proportion has long been used for
textiles and ropemaking. Both fibers can be used in the
preparation of pulp, paper, and probably numerous other products.
An important characteristic of the pulping of hemp compared to
wood is the treatment neccessary to produce pulp is milder.

These and other data have raised the possibility of new approaches
to pulp manufacturing that overcome the serious environmental
problems created by the pulp and paper industry and of developing
energy efficient processes.

The production of pulp and paper from hemp consists of various
operations. Preliminary production steps are the seperation of
bark and wood and if storage is required drying or ensiling. The
numerous steps are: pulping, bleaching, waste-water treatment, and
the basic operations in papermaking. All these tasks are being
studied and optimized. The pulping process we have focused on are:
thermomechanical and chemo- thermomechanical pulping, alkaline
extraction, organosolv pulping, and biopulping.

The results obtained are promising and indicate that pulp and
paper can be prepared from hemp using clean processes and that
substantial energy savings can be achieved. Different qualities of
pulp and paper can be produce dependent on the pulping process.


__________________________________________________

VARIATION OF HEMP (CANNABIS SATIVA) FOR STEM YIELD AND STEM
QUALITY RELATED CHARACTERS

E.P.M. De Meyer

CPO, P.O.Box 16, 6700 Wageningen, The Netherlands

The feasibility of the production of cellulose by means of the
annual crop Cannabis Sativa is being studied in the Netherlands.
This paper deals with one of the basic steps of the project, the
establishment of a Cannabis collection and the characterisation of
the populations with respect to yield and quality.

Until now varieties of domesticated Cannabis are selected for the
production of either phloem fibers or narcotic resin. Both groups
are represented in the collection, as well as a third group
consisting of spontaneous populations. The complete collection
contains about 160 more or less distinctive populations. After
evaluation, selected populations will be used in a breeding
programme.

The dry matter production of cannabis plants depends primarily on
the legnth of the inductive photoperiod which determines the
duration of the vegetative period at a certain latitude. The
harvest index - the fraction of the main stems of the total dry
matter - depends on plant habit traits like degree of branching
and internode legnth. A summary of the variation for vegetative
growth will be presented in relation to stem growth parameters as
measured in a field experiment.

The optimal quality properties of cellulose pulp varieties of
Cannabis are still under study but it is already clear that the
available fiber varieties only partially meet the requirements.

Alternative sources of raw materials for paper pulp production are
usually compared with the main source at present which is conifer
wood. A comparison of Cannabis fiber dimensions and conifer wood
dimensions will be presented. Only the fraction of secondary
phloem fibers is similar to conifer fibers. Almost no variation
has been detected for the length of the relatively short wood
fibers of Cannabis, which hampers attempts to improve the quality
of the xylem fraction by means of breeding. The phloem fibers are
considered to be the most valuable components of the stem. A quick
method to estimate phloem fiber content was developed and results
of the evaluation of the collection with respect to fiber content
will be presented. Also a method to estimate the amount of primary
and secondary fibers within the total fraction of phloem fibers
will be discussed.

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Ben Masel,  Director WI NORML  [b--as--l] at [igc.org]  608-257-5456

911 Williamson St, Madison WI 53703

i didn't put politics in the gutter, i found it there.
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